Since the establishment of the Keihoryo (Crime Prevention and Order Maintenance Hall) inside the Ministry of Interior in 1874, the police force of the entire country was under the control of the state until the end of World War II.

With the establishment of the Police Law in 1947, a drastic reform of the police system took place, and in 1948 the police force was separated to National and Regional Police Headquarters, and Local Government Police for municipalities of 5,000 residents or more.

After the revision of the Police Law in 1954, police operations were carried out at each prefectural level, and the National Police Agency was established as a national police organization to give guidance and coordination to prefectural police departments, and this continues to this day.