Before WWII, the Ministry of Justice (Homusho) used to be called the "Shihosho" in Japanese and it had jurisdiction over a wide range of legal and judicial work including judicial administration, that is, supervision of the work of the courts. However, pursuant to the enforcement of the new Constitution and the accompanying Court Organization Law, the courts were separated from the old Ministry of Justice on May 3,1947 and the power concerning the administration of the courts was transferred to the Supreme Court. Thereafter, on February 15, 1948, the Attorney General's Office Establishment Law came into force under which the Ministry of Justice was abolished and replaced by the Attorney General's Office. This Office was established as the supreme legal adviser to the Government to preside over all legal affairs in addition to the business of the old Ministry of Justice, including the deliberation of draft laws and treaties; and the research and study of judicial systems and legislations at home and abroad which used to be handled by the Cabinet Legislative Bureau and, in addition, the work relating to civil and administrative suits in which the State was a party and the protection of human rights all came under the jurisdiction of the Attorney General's Office.
Later, pursuant to reorganization of the government administrative organs on June 1, 1949,the Attorney General's Office (Homucho) was renamed "Homufu" and its inner organs were scaled down from five Assistant Attorney Generals with 16 Bureaus to three Assistant Attorney Generals with 11 Bureaus.
On August 1, 1952, when the government organs were reorganized again, the Attorney General's Office was changed into the Ministry of Justice, accompanied by extensive reorganization. This meant that the Minister of Justice, like in other Ministries, would head the Ministry, abolishing the system of Attorney General and Assistants, and the Vice-Minister of Justice was placed under the Minister. At the same time, three Bureaus, the 1st, 2nd, 3rd Legislation and Opinion Bureaus, which handled legislative work were transferred back to the Cabinet and the Ministry adopted the seven bureau system, that was, Civil Affairs, Criminal Affairs, Correction, Rehabilitation, Litigation, Human Rights and Immigration, as well as the Minister's Secretariat.
Most recently, the Central Government Reorganization Plan was put into effect on January 6, 2001 under which the Ministry abolished the Litigation Bureau and six divisions of other bureaus, and some deliberative councils were restructured or combined. As a result, the Ministry is now composed of six bureaus, namely, Civil Affairs, Criminal Affairs, Correction, Rehabilitation, Human Rights and Immigration, and the Minister's Secretariat.