Abstract—Concrete structures in a marine environment or exposed the salinity are vulnerable due to both physical and chemical deterioration process. A large number of reinforced concrete bridges built during the high economic development period in Japan will be at risk of serious damage caused by salt damage if there are no timely remedial measures. The repair of these structures by conventional methods is costly and difficult in securing traffic regulation. In this study, the authors proposed a new arrangement of galvanic anode system at low cost and convenient in replacement as well as its application to the existing marine structure. Preliminary results from the experiment indicated that this method was effective in corrosion suppression through the recognition of steel depolarization performance. The monitoring of the experiment will be continued with the expectation that the structural longevity will be extended from 20 to 25 years.