To miniaturize an antifouling device to reduce cost.

A conductive paint film 2 is applied to a shell plate or the like of a marine vessel, and a negative electrode 3 is disposed being insulated from the conductive paint film 2. A solar battery panel 1 is direct-coupled to the conductive paint film 2 to apply positive voltage to the conductive paint film 2 and negative voltage to the negative electrode 3. A micro current therefore flows between the conductive paint film 2 and the negative electrode 3 through sea water to prevent ocean organisms from sticking to the shell plate. Because of the direct-coupled structure, a control circuit or the like is dispensed with to miniaturize on the whole. The area of the solar battery panel 1 can be 1/60-1/30 of the area of the conductive paint film 2, so that the solar battery panel itself can be miniaturized.