The Marine Accident Inquiry Agency which investigates and judges the causes of marine accidents from various angles and strives to prevent the recurrence of further marine accidents, began when Regulations for Western Merchant Vessel Captain, Conductor and Engine Driver Licenses and Regulations for Western Vessels Pilot License were established in 1876, and when hearings of seamen became systematized.

With the Mariner's Disciplinary Punishment Law which was enacted in 1897, independent trials were systematized to discipline those crews who caused maritime accidents. In 1940, the Marine Accidents Inquiry Law was enacted for the purpose of searching for causes of maritime accidents, and is hitherto existing.