On June 13, the Diet passed a revision of the Civil Code lowering the age of adulthood to 18 starting in April 2022. The current age of adulthood — 20 — was introduced in 1876. The amendment represents the first change of Japan's age of majority in 142 years.

Even with the revision, the minimum legal age for activities such as drinking, smoking, and various forms of publicly run gambling will be kept at 20. It was also decided to raise the age at which women can marry from 16 to 18, the same age for men. Raising the marriageable age for women had been recommended by the United Nations Committee on the Elimination of Discrimination against Women in 2003.

The Public Offices Election Law was revised in 2015 to lower the minimum voting age from 20 to 18. The Legislative Council, an advisory body for the justice minister, is to continue discussions of the pros and cons over a revision of the Juvenile Law.