In a mirror surface angle adjusting device of the present invention, supplying terminals of a connector is inserted into insertion holes of a case thereby electric power is supplied to a motor within the case. Thus the motor is driven to adjust the mirror surface angle of the mirror body. A closing plate of the connector substantially closes the interior of first waterproofing walls provided on a periphery of the insertion holes. A second water proofing wall is provided at the connector. In this way, it is possible to suppress entering of water into the first waterproofing walls.