Is a work-interval (rest between shifts) system an obligation? The content of the effort obligation and how to put it in your work rules

In short: A work-interval system secures a set rest period between the end of one day's work and the start of the next. It is an effort obligation under Article 2, paragraph 1 of the Act on Special Measures for Improvement of Setting of Working Hours (added by the Work Style Reform Act, in force from April 1, 2019). Because the Act sets no specific number of hours, each company decides how many hours to leave in its work rules or a labour-management agreement. Introducing it does not make the 36 Agreement or the upper limits on overtime (Labor Standards Act, Article 36) disappear; you need a design that satisfies both. From the viewpoint of a shakai hoken roumushi's labour management, this page sets out the positioning of the effort obligation, the design of the rest period and exemptions, how to write it into work rules and labour-management agreements, consistency with the upper limits, the support (subsidy) framework, and operation on sites with many shifts and late-night duties.

On sites with long hours or late-night duties, situations such as "overtime one day overlaps with an early start the next, leaving almost no rest" easily arise. This page is for managers and labour staff of small and medium companies who are unsure whether to introduce a work interval and how to write it into their work rules. It sets out the reach of the effort obligation, the design of the rest period, the work rules and agreements, the relationship with the 36 Agreement and the upper limits, the support system, and realistic operation.

What is a work-interval system, and is it an obligation or an effort obligation?

A work-interval system secures a set rest period (interval) between the previous day's finishing time and the next day's starting time. The basis is Article 2, paragraph 1 of the Act on Special Measures for Improvement of Setting of Working Hours (Act No. 90 of 1992), which provides that an employer must endeavour to take the necessary measures, including "setting the time from finishing to starting work necessary to secure health and welfare." This was added by the Work Style Reform Act (Act No. 71 of 2018) and came into force on April 1, 2019.

The point to grasp here is that it is an effort obligation, not an obligation. Not introducing it does not immediately bring a penalty. That said, the Outline of Measures for the Prevention of Death from Overwork sets numerical targets, and the country is moving to spread the system.

Category	Content
Positioning	Effort obligation (Act on Improvement of Setting of Working Hours, Article 2, paragraph 1)
In force	April 1, 2019 (added by the Work Style Reform Act)
Statutory number for the rest period	None in the Act (each company sets it)
Penalty	None (because it is an effort obligation)

How many hours of rest should you leave, and what exemption designs are possible?

The Act sets no specific number of hours for the rest. Each company decides how many hours to secure. In practice, 9 hours or 11 hours are often used as a guide, but these are not numbers the Act fixes uniformly; they are operational guides drawn from the requirements of the support (subsidy) described below and from the European system.

Once you set a rest period, cases arise where "the previous day's overtime runs over and the rest period cannot be secured before the next day's scheduled start." There are mainly two approaches to this, and you clarify them in the work rules.

Design	Content
Push back the start	Move the next day's starting time later, and either treat the pushed-back time band as worked (without cutting pay) or have the person work as scheduled
Manage so it is never undercut in the first place	Manage the overtime cap and finishing time so the rest period is not undercut

Also, it is common to list in advance, in a limited way in the work rules and agreement, the exemptions (cases where the interval need not be secured), such as where there is a temporary need due to a disaster or other unavoidable reason. Widening the exemptions too far hollows out the system, so the scope is kept narrow. A qualified professional designs how many hours to set and how far to allow exemptions, to fit the reality of the work.

How do you write it into work rules and agreements, and reconcile it with overtime and night duty?

A workplace that regularly employs 10 or more workers has a duty to draw up and file work rules (Labor Standards Act, Article 89); if you introduce a work interval, you set the length of the rest period, the treatment of a pushed-back start, and the exemptions in the work rules. There is also a design in which you conclude a labour-management agreement as well, clarifying who is covered and how it operates.

At workplaces with late-night duties or night duty, how the rest period is counted changes depending on whether the night duty counts as intermittent work approved by the head of the Labour Standards Inspection Office (Labor Standards Act, Article 41, item 3) or is, in reality, ordinary work. Even an approved night duty is working time if the reality of the nap or standby amounts to work (the thinking on night-duty approval is covered in Standards for night-duty approval). For doctors, a work interval is mandatory as a health-securing measure at medical institutions on a level that relaxes the upper limit on working hours, which differs from the general system that stays an effort obligation (covered in Doctors' overtime upper limit and securing health).

When you introduce it, how does it relate to the 36 Agreement and the upper-limit regulation on overtime?

Even if you introduce a work interval, the upper-limit regulation on overtime and holiday work (Labor Standards Act, Article 36) applies separately. You must satisfy both. Overtime set by a 36 Agreement is in principle within 45 hours a month and 360 hours a year, and even a special clause cannot exceed the following.

Item	Upper limit
Overtime (in principle)	45 hours a month, 360 hours a year
Annual limit of the special clause	Within 720 hours a year
Single month (overtime + holiday work)	Under 100 hours
Multi-month average (overtime + holiday work)	Within 80 hours for any 2–6-month average
Number of times a month may exceed 45 hours	Up to 6 times a year

A work interval secures "rest until the next day," while the upper-limit regulation suppresses "the total within a period" — different roles. Designing both at once lets you suppress long hours from both the entrance (total) and the exit (rest). The design of the 36 Agreement itself is in How far can a 36 Agreement allow overtime, and the lawful requirements for paying premiums as a fixed overtime allowance are in Lawful requirements for a fixed overtime allowance.

What support (subsidy) framework is available to companies that introduce it?

For small and medium companies newly introducing a work-interval system, there is a support framework called the Work Style Reform Promotion Support Subsidy (Work Interval Introduction Course). It supports introducing a system that sets a certain rest period (for example, categories of 9 hours or more and 11 hours or more), targeting measures such as training, awareness-raising, and the introduction of equipment that helps with working-hour management.

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However, the maximum amount, subsidy rate, application deadline, and requirements change each fiscal year, and the acceptance period is limited. Be sure to check the specific amounts and deadlines in the latest call guidelines for that fiscal year published by the Ministry of Health, Labour and Welfare and each Labour Bureau before applying (this article does not give amounts or deadlines that vary by year as fixed values).

The Outline of Measures for the Prevention of Death from Overwork (cabinet decision of July 30, 2021) set a numerical target of raising the share of companies that have introduced a work-interval system to 15% or more by 2025. The outline was later revised in August 2024, extending the target deadline and reviewing the scope of covered companies. The introduction share shown by the General Survey on Working Conditions still falls short of the target (referenced October 17, 2026, against Ministry of Health, Labour and Welfare materials).

How do you realistically run it on sites with many shifts and late-night duties?

On shift-based sites with late-night duties, it is realistic not to leave the system as a mere "rule" but to build the rest period into the stage of making the shift schedule. Designing in the following order makes it easier to run.

Step	Content
1	Decide how many hours the rest period is, and state it clearly in the work rules
2	At the point of making the schedule, screen out shifts where the gap from one shift's end to the next shift's start undercuts the rest period
3	Set the treatment of a pushed-back start when overtime undercuts the rest period
4	List the exemptions (disasters, etc.) in a limited way
5	Record the actual intervals in the attendance system and make undercuts visible

At late-night and rotating-shift workplaces, you design it together with the variable working-hour system and how the shifts are built. A qualified professional judges how many hours to set as the rest period and which exemptions to allow, taking into account the site's staffing and the ebb and flow of work.

What can 四葉社会保険労務士事務所 do for you?

四葉社会保険労務士事務所 in Kohinata, Bunkyo Ward, handles, for a work-interval system, designing the rest period, reflecting it in the work rules and labour-management agreement, checking consistency with the 36 Agreement and the overtime upper limit, designing operation including shifts and night duty, and providing information on the content of the support (subsidy). The initial consultation is free. We quote according to the content and the number of employees; for how fees are thought about, see the fee schedule, and the questions we are asked most often are collected on the FAQ page.

Where you wish to have a subsidy application handled, this office takes it on within the scope of providing information and procedures for labour management, and the Labour Bureau decides the individual eligibility.

Frequently asked questions

Q. Is there a penalty if we do not introduce a work-interval system?
A. No. A work interval is an effort obligation under Article 2, paragraph 1 of the Act on Improvement of Setting of Working Hours, in force from April 1, 2019. There is no penalty for not introducing it in itself, but the Outline of Measures for the Prevention of Death from Overwork sets numerical targets, and the country is promoting it. If you introduce it, reflecting it in the work rules and reconciling it with the upper-limit regulation are the practical issues.

Q. How many hours should the rest period be?
A. The Act sets no specific number of hours. Each company decides how many hours to secure in its work rules or a labour-management agreement. In practice, 9 or 11 hours are often used as a guide, but these are guides drawn from the requirements of the support system and the European system, not numbers the Act fixes uniformly. You design it to fit the reality of the work.

Q. If we introduce a work interval, do the 36 Agreement and the upper-limit regulation on overtime stop applying?
A. No. A work interval is "securing rest until the next day," while the upper-limit regulation on overtime and holiday work (Labor Standards Act, Article 36) is "suppressing the total within a period" — different roles, and you must satisfy both. The limit is in principle 45 hours a month and 360 hours a year, and even a special clause is within 720 hours a year, under 100 hours in a single month, within an 80-hour multi-month average, and may exceed 45 hours up to 6 times a year.

Q. Is there a subsidy that supports introduction?
A. For small and medium companies newly introducing a work-interval system, there is a framework called the Work Style Reform Promotion Support Subsidy (Work Interval Introduction Course). However, the maximum amount, subsidy rate, application deadline, and requirements change each fiscal year, and the acceptance period is limited. Check the latest call guidelines for that fiscal year from the Ministry of Health, Labour and Welfare and each Labour Bureau before applying.

Sources for this article

• Act on Special Measures for Improvement of Setting of Working Hours (労働時間等の設定の改善に関する特別措置法, Act No. 90 of 1992), Article 2, paragraph 1 (the employer's responsibility: the effort obligation to take necessary measures including "setting the time from finishing to starting work necessary to secure health and welfare"). The work-interval effort obligation was added by the Work Style Reform Act (Act No. 71 of 2018), in force from April 1, 2019 (confirmed against e-Gov on October 17, 2026)
• Labor Standards Act (労働基準法, Act No. 49 of 1947), Article 36 (the agreement on overtime and holiday work and the upper-limit regulation: in principle 45 hours a month and 360 hours a year, even a special clause within 720 hours a year, under 100 hours in a single month, within an 80-hour multi-month average, and exceeding 45 hours up to 6 times a year), Article 89 (drawing up and filing work rules), Article 41, item 3 (intermittent work: night-duty approval)
• Outline of Measures for the Prevention of Death from Overwork (cabinet decision of July 30, 2021; numerical target of raising the share of companies that have introduced a work-interval system to 15% or more by 2025). Revised August 2024, extending the target deadline and reviewing the scope. The introduction share shown by the General Survey on Working Conditions falls short of the target (referenced October 17, 2026, against Ministry of Health, Labour and Welfare materials)
• Ministry of Health, Labour and Welfare, "Work Style Reform Promotion Support Subsidy (Work Interval Introduction Course)." Because the maximum amount, subsidy rate, application deadline, and requirements vary by fiscal year, amounts and deadlines are not given as fixed values (referenced October 17, 2026)

This article does not go so far as to decide whom you should consult. Designing the rest period of a work interval, reflecting it in the work rules and labour-management agreement, reconciling it with the 36 Agreement and the overtime upper limit, and designing operation including shifts and night duty are the work of a shakai hoken roumushi. The cost of consulting 四葉社会保険労務士事務所 is set out in the fee schedule, and the questions we are asked most often are collected on the FAQ page.

This article is general information. Judgments that fit your particular circumstances are made by a qualified professional after a meeting. Written by Joji Uramatsu (Shakai Hoken Roumushi (Certified Social Insurance and Labor Consultant), Gyoseishoshi (Certified Administrative Procedures Legal Specialist), Registered Real Estate Transaction Specialist).