Mental Health Measures in the Workplace under Japanese Labour Law

In Japan, workplace mental-health protection is not limited to counselling after an employee becomes ill. The legal framework increasingly requires employers to prevent excessive psychological burden, identify workplace stress, provide medical intervention where required, protect health information, prevent harassment, and adjust work where health risks become apparent.

The principal legal framework consists of the Industrial Safety and Health Act (労働安全衛生法), the Labour Contract Act, Article 5 (安全配慮義務), the Mental Health Promotion Guidelines, the Stress Check system, rules concerning excessive working hours, and the Power Harassment Prevention framework.

MHLW expressly describes the employer's obligation as including attention to workplace conditions affecting mental health, even where the employee has not personally reported the problem.

1. Meaning of workplace mental-health measures

Workplace mental-health measures are the policies and actions adopted by an employer to:

• prevent psychological illness;
• reduce excessive psychological burden;
• identify workplace stress;
• respond to depression and other mental-health conditions;
• prevent suicide and karoshi;
• prevent power harassment and other harassment;
• provide access to occupational physicians and counselling;
• facilitate medical leave and return to work;
• protect confidential health information;
• adjust workloads where necessary; and
• continuously improve the psychological work environment.

Japanese law therefore adopts both a preventive and responsive approach.

2. Employer's duty of care

Article 5 of the Labour Contract Act provides the statutory foundation for the employer's duty to give necessary consideration so that workers' life and physical safety, including mental and physical health, are protected while working.

This duty is important because mental-health problems may not be voluntarily disclosed by employees.

MHLW's explanation of Japanese case law states that employers have a safety-consideration duty regarding workers' life, body and health and that, because employees may find it difficult to disclose mental-health problems, employers must pay adequate attention to working conditions even without an employee's explicit report.

3. Four-stage approach to mental-health management

A practical Japanese workplace system can be divided into four stages.

Stage 1 — Primary prevention

The employer attempts to prevent mental-health problems before they arise.

Measures include:

• reasonable workloads;
• working-hour management;
• adequate staffing;
• rest and leave;
• anti-harassment systems;
• management training;
• stress surveys;
• workplace-environment improvement;
• employee consultation systems.

The Stress Check system is principally a primary-prevention mechanism. MHLW describes its purpose as helping workers recognize their own stress and improving working environments that generate stress.

Stage 2 — Early detection

Employers should identify warning signs such as:

• repeated absence;
• significant deterioration in performance;
• sleep-related complaints;
• excessive overtime;
• behavioural changes;
• complaints of harassment;
• requests for workload reduction;
• unusually high stress-check results.

Stage 3 — Treatment/support

Appropriate responses may include:

• occupational physician consultation;
• medical referral;
• workload reduction;
• transfer where appropriate;
• leave;
• flexible working arrangements;
• counselling;
• employee-assistance programmes.

Stage 4 — Return to work

A return-to-work programme should consider:

• medical opinion;
• fitness for work;
• gradual resumption;
• reduced workload where appropriate;
• working hours;
• follow-up monitoring;
• recurrence prevention.

4. Stress Check system

The Industrial Safety and Health Act, Article 66-10 establishes the statutory stress-check framework.

The employer must arrange for workers to undergo a psychological-burden examination by a physician, public-health nurse or other legally qualified person under the prescribed rules.

The system has several important protections.

Individual results

Stress-check results are communicated to the worker by the medical professional.

The employer does not automatically receive individual results without the worker's consent, subject to the statutory framework.

Interview with physician

Where the statutory conditions are satisfied and the worker requests an interview, the employer must arrange the appropriate physician interview.

Employment protection

An employee must not be disadvantaged merely because the employee requested the statutory interview or participated in the stress-check process.

Workplace improvement

The system is not merely an individual diagnosis mechanism. Aggregate workplace information can be used to identify stressful organisational environments and improve working conditions.

5. Mental-health measures and excessive working hours

Long working hours are particularly important because psychological burden can accumulate progressively.

The employer should therefore monitor:

• overtime;
• consecutive working days;
• insufficient rest;
• night work;
• workload increases;
• staffing shortages;
• unrealistic deadlines;
• excessive responsibility;
• employee requests for assistance.

The leading Dentsu case established that an employer has a duty to prevent excessive accumulation of fatigue and psychological burden arising from work.

6. Six important Japanese cases

Case 1 — Dentsu Case

Supreme Court, Second Petty Bench, 24 March 2000

This is one of Japan's leading cases concerning workplace mental health and overwork.

The employee suffered depression following prolonged excessive working hours and subsequently died by suicide. The Supreme Court recognised the employer's duty to ensure that excessive fatigue and psychological burden associated with work did not damage the employee's physical or mental health.

The Court found that superiors knew of the employee's excessive workload and deteriorating health but failed to take appropriate workload-reduction measures.

Principle

Employers must actively manage excessive psychological and physical workload once the circumstances reasonably indicate a health risk.

This case is foundational for:

• workload monitoring;
• overtime control;
• manager responsibility;
• mental-health prevention;
• employer safety obligations.

Case 2 — Toshiba Case

Supreme Court, Second Petty Bench, 24 March 2014

This case concerned an employee who developed serious mental-health problems while working for Toshiba.

The MHLW's case-law summary explains that the employee experienced insomnia and other health problems, requested reduction of workload, but was subsequently assigned additional work; eventually the employee took leave and the employment relationship ended.

Principle

An employer's mental-health obligations cannot be evaluated solely by asking whether the employee formally declared a diagnosed psychiatric condition.

The employer must consider:

• known symptoms;
• requests for workload adjustment;
• changes in working conditions;
• medical information appropriately available to the employer;
• the employer's own knowledge of deteriorating health.

HR significance

Where an employee repeatedly requests workload reduction because of health problems, simply continuing to increase the workload can create substantial legal risk.

Case 3 — Dentsu Case on occupational mental-health causation

The Dentsu litigation is also significant because it demonstrates the relationship between:

excessive working hours → psychological exhaustion → depression → suicide → employer liability.

The Supreme Court recognised that prolonged exhaustion and psychological stress can damage mental health and that management personnel exercising supervisory authority must act consistently with the employer's duty of care.

Principle

Managers are not merely responsible for completing business objectives. Their supervisory authority must be exercised consistently with employee health protection.

Case 4 — 2025 Prefectural Police Inspector Case

Supreme Court, Second Petty Bench, 7 March 2025

This is a particularly important modern decision.

A police inspector experienced:

• a substantial increase in overtime;
• more than 112 hours of overtime in the month immediately before the suicide;
• repeated periods of 14 consecutive working days;
• multiple shifts exceeding 24 hours;
• additional significant work;
• a severely adverse stress-test result.

A superior knew about the stress-test result, while management failed to take concrete measures to reduce the employee's burden.

The Supreme Court held that the relevant authority had a duty to protect the employee's physical and mental health from excessive fatigue and psychological burden and that failure to take appropriate workload-reduction measures could result in liability.

Importance

This case demonstrates that stress-check information can become highly significant when management actually knows the employee is experiencing serious stress.

It also shows that courts can consider the totality of working circumstances, rather than relying only on a numerical overtime threshold.

Case 5 — Fire Defence / Power Harassment Case

A recent Supreme Court case concerning a fire-defence employee involved repeated abusive conduct toward subordinates, including conduct carried out under the guise of training and guidance.

The record included workplace complaints that power harassment was prevalent and that young employees had experienced serious psychological consequences.

Principle

Training and managerial guidance cannot be used as a justification for conduct that crosses the boundaries of legitimate supervision.

Mental-health relevance

Employers should therefore distinguish:

legitimate managerial instruction

from

humiliating, abusive, intimidating or degrading conduct.

Mental-health protection requires effective prevention and investigation of workplace harassment.

Case 6 — Mental-disorder occupational-injury case involving workplace power harassment

MHLW's Labour Insurance Appeals Board has considered numerous occupational-disease cases involving psychological disorders caused by workplace stressors.

For example, the 2014 decisions include a case in which a mental disorder and subsequent suicide were attributed to workplace power harassment by a superior. The Board also considered cases involving psychological disorders caused by workplace harassment and other employment-related stressors.

Similarly, the 2015 decisions included a case where a worker's mental disorder was attributed to daily power harassment by managers, resulting in cancellation of the earlier adverse decision.

Principle

Mental-health risk is not limited to working hours.

It can arise from:

• harassment;
• humiliation;
• excessive criticism;
• unreasonable targets;
• interpersonal conflict;
• job transfer;
• excessive responsibility;
• organisational restructuring.

7. Power harassment prevention

Japanese employers should establish a formal harassment-prevention structure.

This should include:

Prevention

• written anti-harassment policy;
• management training;
• employee training;
• examples of prohibited conduct;
• senior-management commitment.

Reporting

Employees should have:

• internal consultation channels;
• HR reporting;
• compliance/ethics channels;
• confidential reporting mechanisms;
• appropriate external consultation where necessary.

Investigation

Complaints should be:

• promptly assessed;
• investigated impartially;
• documented;
• handled confidentially;
• followed by appropriate corrective action.

Protection against retaliation

Employees should not be disadvantaged for raising legitimate workplace-health or harassment concerns.

8. Confidentiality of mental-health information

Mental-health information is particularly sensitive.

HR should therefore apply strict controls to:

• psychiatric diagnoses;
• medical certificates;
• stress-check results;
• counselling records;
• occupational physician opinions;
• return-to-work assessments;
• disability-related information.

The stress-check framework specifically contains rules concerning the appropriate handling of health information. MHLW's guidelines address confidentiality and restrictions on disadvantageous treatment.

A manager normally does not need to know an employee's entire medical history simply because the employee requires a workplace adjustment.

9. Manager responsibilities

Managers are particularly important because they often observe problems before HR does.

Managers should be trained to recognise:

• dramatic workload increases;
• repeated overtime;
• unexplained absence;
• deterioration in behaviour;
• workplace conflict;
• harassment complaints;
• employee requests for assistance;
• signs of severe fatigue;
• stress-check information where lawfully disclosed.

The manager should not attempt to diagnose a psychiatric condition.

Instead, the appropriate response is generally:

1. listen;
2. document relevant workplace issues;
3. reduce immediate workplace risks where appropriate;
4. refer the employee to HR/occupational health;
5. obtain appropriate professional advice;
6. monitor the workplace situation.

10. Workload adjustment

Workload adjustment is one of the most important legal responses.

Possible measures include:

• reducing overtime;
• reallocating tasks;
• postponing non-essential deadlines;
• increasing staffing;
• changing shifts;
• reducing travel;
• temporary reassignment;
• modifying working hours;
• allowing leave;
• introducing gradual return to work.

The 2025 Supreme Court police case is particularly instructive because the Court focused on management's failure to take concrete measures to reduce the employee's burden despite circumstances indicating serious psychological risk.

11. Return-to-work programmes

An employee returning after mental-health leave should not necessarily be returned immediately to the exact workload previously performed.

A structured programme can include:

Step 1: medical assessment
Step 2: occupational physician review
Step 3: return-to-work plan
Step 4: reduced workload/hours where appropriate
Step 5: monitoring
Step 6: gradual restoration of normal duties
Step 7: recurrence-prevention measures.

The purpose should be sustainable return to work rather than merely ending leave as quickly as possible.

12. EAP and counselling systems

An employer may establish:

• Employee Assistance Programmes;
• confidential counselling;
• occupational-health consultation;
• psychological support;
• external counselling services;
• crisis-response systems.

However, counselling should supplement, not replace, organisational measures.

For example, sending an employee to counselling while leaving the underlying problem of extreme overtime or harassment unchanged may fail to address the workplace risk itself.

13. Mental health and workplace surveys

Employers can use:

• stress surveys;
• engagement surveys;
• harassment surveys;
• absenteeism data;
• overtime data;
• turnover data;
• return-to-work data;
• employee complaints.

But HR must avoid using surveys merely as statistical exercises.

The results should lead to:

identify → analyse → intervene → monitor → reassess.

The statutory stress-check system itself is designed not only around individual stress awareness but also around improving workplace conditions.

14. Mental health and remote/hybrid work

Modern mental-health measures should also address:

• excessive digital availability;
• isolation;
• excessive online meetings;
• blurred working hours;
• inability to disconnect;
• inadequate communication;
• workload invisibility;
• reduced managerial contact.

Remote work does not eliminate the employer's responsibility to manage excessive workload and psychological burden.

15. Mental health and AI/algorithmic management

Modern employers should additionally consider whether algorithmic systems create psychological risks through:

• excessive productivity targets;
• automated performance monitoring;
• unrealistic scheduling;
• constant alerts;
• automated ranking;
• surveillance;
• unpredictable work allocation.

Where technology materially increases psychological burden, employers should examine the resulting workplace conditions rather than treating the algorithm as independent from managerial responsibility.

16. HR compliance checklist

A Japanese employer should maintain at least the following:

17. Six core legal principles from the cases

The Japanese cases collectively demonstrate the following:

1. Mental health is part of the employer's safety obligation

The duty of care extends to mental as well as physical health.

2. Excessive workload creates legal risk

Long working hours and accumulated psychological burden can establish employer responsibility where the employer fails to respond appropriately.

3. Employee silence is not always a defence

MHLW recognises that mental-health problems can be difficult for employees to disclose; employers therefore have responsibilities concerning workplace conditions even without an explicit complaint.

4. Management knowledge matters

Once supervisors possess relevant information indicating serious stress or deteriorating health, the need for concrete intervention becomes particularly important. The 2025 Supreme Court decision illustrates this clearly.

5. Harassment can be a mental-health hazard

Power harassment can constitute a significant psychological burden and may contribute to occupational mental disorders.

6. Prevention is preferable to post-incident response

The statutory stress-check framework is expressly designed around prevention and workplace improvement, rather than merely identifying already-ill employees.

Conclusion

Japanese workplace mental-health law increasingly requires an organisational risk-management approach, rather than simply asking employees to seek counselling when they become ill.

The employer should therefore operate a continuous cycle:

identify psychological risks → monitor workload and stress → prevent harassment → provide consultation → conduct stress checks → intervene when risks emerge → adjust working conditions → support leave and return to work → monitor recurrence.

The most important legal principle is the employer's 安全配慮義務 (duty to take care for employee safety and health). The Dentsu jurisprudence established the central connection between excessive fatigue/psychological burden and employer responsibility, while the Toshiba and 2025 police-inspector decisions demonstrate the continuing importance of management's response to known or reasonably foreseeable mental-health risks.

Note: The six authorities above include Supreme Court judgments and Labour Insurance Appeals Board decisions; they should be distinguished from one another because an occupational-injury/insurance determination and a civil damages judgment do not operate in exactly the same procedural or remedial framework.