The legislation permits the first abdication by a Japanese monarch since Emperor Kokaku in 1817 during the latter part of the Edo Period, CNN reported. The royal male line in Japan is unbroken, records show, for at least 14 centuries.
Akihito, 83, who has had heart surgery and treatment for prostate cancer, said last year he feared age might make it difficult for him to continue to fulfill his duties, Reuters reported.
Akihito is the first Japanese emperor who was never considered divine. He has worked for decades to soothe the wounds of World War II, fought in the name of his father, Hirohito. Akihito will be succeeded by Naruhito, 57, the eldest of his three children, probably next year, Reuters reported.
"Abdication will take place for the first time in 200 years, reminding me once again of how important an issue this is for the foundation of our nation, its long history, and its future," Prime Minister Shinzo Abe told reporters.
"In essence, the emperor is resigning, which I feel was an issue of personal thought," said Masayoshi Matsumoto, a 47-year-old animator.
The law applies only to Akihito and not to future emperors, Reuters reported.