The Act began life in 1993 as the Part-Time Work Act. The Work Style Reform extended it to fixed-term employees and renamed it, so that one statute now covers both groups. Whether someone counts as part-time depends on their hours compared with regular staff at the same employer, not on their job title. A contract employee working full-time hours on a one-year contract is covered as a fixed-term worker.
The Act does three main things. It bans unreasonable differences in pay and treatment compared with regular employees, judged item by item under Article 8, and bans any difference at all where the job and the scope for future changes in role and location are the same, under Article 9. It requires employers to give these workers written terms covering matters such as pay rises, bonuses, retirement allowances and who to consult. And under Article 14, the employer must explain the reasons for any difference if a worker asks, and must not treat them worse for asking. Employers must also take steps to help these workers move into regular roles, for example by telling them about permanent vacancies.
The latest change is procedural. From 1 October 2026, the written terms given at hiring and at each renewal must state that the worker can ask for an explanation of how and why their treatment differs from regular staff. The government's equal-pay guidelines were revised at the same time to say more about bonuses, retirement allowances and other allowances.
What it means for a foreign employer
- It reaches more of your staff than you think. Contract staff, re-employed retirees and part-time specialists are all covered, including at a small Japan entity.
- Update your templates now. Hiring and renewal documents issued from October 2026 need the new statement on the right to ask for reasons.
- Prepare the explanation before the question. A refusal, or a vague answer, is a breach in itself. Keep a written rationale for each allowance and benefit that regular staff get and others do not.
- Senior contract hires are not exempt. A highly paid fixed-term executive is still a fixed-term worker. The Act rarely bites at that level, but the conversion and renewal rules in the Labour Contract Act do.
Sources
- Act on Improvement of Employment Management for Part-Time and Fixed-Term Workers, Articles 6, 8, 9, 13 and 14 (as amended in force April 2020, and April 2021 for small and medium-sized employers).
- Ministry of Health, Labour and Welfare, amended enforcement regulations and Equal Pay for Equal Work Guidelines, promulgated 28 April 2026, in force 1 October 2026.