A floating structure is viewed as a "moored vessel" by the Maritime Bureau of the Ministry of Land, Infrastructure and Transport (MLIT) in Japan from the viewpoint of vessels, while it is viewed as a "facility of a port" by the Ports and Harbors Bureau, and as a "marine structure" by the Housing Bureau of MLIT, noting its similarities in usage with a structure on land. That is to say, for the safety of the structure, application of the Law for Safety of Vessels, the Port Act and the Building Standard Law (including the Fire Service Law) are required under each system of law, respectively. However, the present two cases are exempt from the application of these laws. It is hoped that various systems of laws and regulations would be a chance rather than an obstacle, for the facilitation of new and positive utilization of sea areas in the future.