From Job Offer to Your First Day: Working Conditions and Social Insurance

In many cases, a job offer is viewed as a labour contract that has already been formed, with a fixed start date and with the company reserving a right to cancel it if certain grounds arise. Because the contract already exists, it is more than a notice of a plan. Cancellation is limited to cases based on facts the company could not have known at the time of the offer and that are objectively reasonable and socially acceptable, so it is not a promise the company can break at any time without reason. Whether you submitted an acceptance form does not by itself decide whether the offer has effect.

The MHLW Q&A says declining a job offer is basically not a problem, but if it is done in a way that seriously breaches good faith, the company could possibly seek damages. No one can be forced to work against their will, so the claim that an accepted offer can never be declined is wrong. The Labour Standards Act (Rōdō Kijun Hō) also prohibits setting penalties in advance, so you do not always have to pay one. Contacting the company only after the start date is not a sincere way to handle it; once you decide, tell them early.

From April 2024, when a labour contract is made (and when a fixed-term contract is renewed), employers must show the "scope of change" for the place of work and the duties, for all workers. This lets you check the range of possible transfers or reassignments before you join. Pay raises are not among the items that must be given in writing, and no new duty to show an exact raise amount was added. Staff numbers, average age and sales revenue are not working conditions that must be shown.

The items that must be given in writing are: the contract period, the criteria for renewing a fixed-term contract, the place of work and duties, start and finish times, breaks, days off and leave, how wages are set, calculated and paid along with the closing and payment dates, and matters about leaving the job (including grounds for dismissal). Within wages, matters about pay raises must be explained but are excluded from the written-document requirement. The contract period, working times and days off, and leaving the job must all be given in writing.

Court precedent treats an ordinary probation period as a labour contract in which a right to cancel is reserved, so the contract already exists. Refusing permanent employment is allowed more widely than an ordinary dismissal, but only when there is an objectively reasonable reason that is socially acceptable. The idea that no contract exists and the company can refuse freely is wrong. The law sets no fixed length for probation; about three months is simply common. The Labour Standards Act applies during probation too.

Under this rule, when fixed-term labour contracts with the same company are renewed and the total exceeds five years, the contract becomes one with no fixed term if the worker applies, and the company cannot refuse. No company approval is needed, so the claim that conversion depends on the company is wrong. The period is more than five years, not one or three, and the worker's application is required. Also, an indefinite-term contract is not necessarily the same as becoming a "regular employee".

Annual paid leave of 10 days is given after six months of continuous service with attendance on at least 80% of all working days, and it increases with length of service up to a maximum of 20 days. By law, it is not given immediately on the day you join. The condition is attending at least 80% of days, not never taking a day off, and the period is six months, not one year. Part-time workers also receive it according to the number of days they work, so it is not only for regular employees.

The regional minimum wage (chiikibetsu saitei chingin) is set for each prefecture. In the fiscal 2026 revision, the national weighted average is 1,177 yen per hour (highest 1,280 yen, lowest 1,085 yen), taking effect in stages between October 1 and December 2, 2026. Because the amounts differ by prefecture, it is not the same nationwide. The minimum wage applies to all workers, including part-time workers and foreign nationals. Even if the worker agrees, a wage set below the minimum wage is invalid.

Part-time workers join if they have 20 or more contracted working hours a week, are expected to be employed for more than two months, are not students, and work for an employer of the threshold size (51 or more employees as of October 2026, planned to widen to 36 or more from October 2027). The pay requirement of 88,000 yen or more a month was abolished in October 2026, so the claim that monthly pay alone decides it is wrong. Part-time workers do join if they meet the conditions. The 10-hours-a-week figure refers to the expansion of Employment Insurance (koyō hoken) from October 2028, not to Health Insurance or the Employees' Pension Insurance.

The General Labour Consultation Corner is located in places such as Prefectural Labour Bureaus (rōdō kyoku) and Labour Standards Inspection Offices (rōdō kijun kantokusho). It is free, needs no appointment, and handles many workplace issues, including recruitment and hiring. Students and job seekers can use it, and consultations in multiple languages are available for foreign residents. The resident registration, tax return and pension benefit counters handle procedures for addresses, taxes and pensions, not labour-condition disputes. If the job was posted through Hello Work, you can also report it to Hello Work.