It is often observed that coastal facilities are damaged by undesirable impacts resulting from the settlement of structures, destruction of structure components and so on. In order to keep the function of facilities in good condition, it is important to maintain the facilities effectively. 　From this point of view, this paper makes clear the characteristics of deterioration of facilities and finds out the relation between deterioration of facilities and the causes as well. Based on these results, effective maintenance method of coastal facilities is developed. The method consists of inspections, evaluations and repair works.