This paper is an examination of the definition of ship in the Maritime Public Law. The systems of the Ship Safety Law will be examined by using coastal non-self-propelled ships excluded from the Ship Law as a matter. The Ship Safety Law allows the ship to enter the coastal state based on the provisions of navigation arear in outside of Japan. Maintaining maritime peace requires demarcating the status of the vessel's maritime law. The argument consideration and examines the current state of domestic and international law, the history of drafting and political background, government documents and prior studies. As a result of verification, there is a discrepancy in the legal system that includes the ship in the framework of the Ship Safety Law. The basis of the system for setting up grounds for establishment of navigation arear in outside of Japan is based on the reciprocity of the “Convention on the International System of Seaports”. Ships that use the system for setting up for the establishment of navigation arear outside of Japan must be legally regulated to exercise the responsibility of the jurisdiction of the Flag State. In summary, we proposed the formulation of a system of jurisdiction that is effective in protecting marine safety and the environment for coastal non-self-propelled ships in Japan.