There are the many historical port facilities in a port of our county, and these have high potential to contribute to comfortable local environmental creation. However, it decrease without the value being recognized by many of historical port facilities continuing a function at the present. On a preservation of such historical port facilities, security by a legal system is effective. Therefore this study assumed that it was clear about a preservation method of the historical port facilities through a legal system. 1. For the historical port facilities like buildings and civil structures as one need to adapt substance designate of group designate depending on geographical conditions. 2. As for the regulation contents of a legal system, it is wished the status quo is a principle for the historical port facilities. However, the regulation content that a valuable part is left for of the historical port facilities is expected at the time of continuation / conversion of a function for it with change.