[Legislations on radiation in Japan].

The Atomic Energy Basic Act was the first law for the prevention of radiation damage in Japan, and was enforced in 1955. The law focused on the research, development and promotion of the use of atomic energy. With an increase in the importing of radioactive isotopes from foreign countries, the Act on Prevention of Radiation Disease Due to Radioisotopes was established under the jurisdiction of the Science and Technology Agency in 1957 and enforced in 1958. The Nuclear Regulation Authority began as an extra-ministerial committee of the Ministry of the Environment in 2012 and has jurisdiction in the area of ionizing radiations regulations.Substantial regulation has been provided by the Labor Standards Act, and the Ordinance on Prevention of Ionizing Radiation Hazards was established as the eleventh ordinance of the Ministry of Labor in 1959. There have been many revisions to the Ordinance, including revisions following the Fukushima Daiichi Nuclear Power Plant accident in 2011. This paper explains the Act on Prevention of Radiation Disease Due to Radioisotopes, the Ordinance on Prevention of Ionizing Radiation Hazards, and workmen's accident authorization.