To provide a galvanic corrosion preventing bolt which is excellent in the handleability without causing the galvanic corrosion on a member to be fastened when members made of different metals are brought into contact with each other and are fixed by fastening them by means of a bolt.

The galvanic corrosion preventing bolt 25 is composed of a bolt 20, and a washer 22 having a through hole 22a for inserting the threaded portion of the bolt 20 thereinto. At least any one of the bolt 20 and the washer 22 is processed by the surface treatment for preventing the galvanic corrosion. Then, the threaded portion of the bolt is inserted into the washer 22, and the washer 22 is brought into contact with the lower surface of the head of the bolt, and then is fixed.