Foreign matter is effectively ejected from between a sliding portion and protruding portions. In a mirror surface angle adjustment device of a vehicle door mirror device, while a mirror holder is rotated and an angle of a mirror surface of a mirror is adjusted, a sliding portion of the mirror holder slides on protruding portions of the case. The protruding portions extend to be directed toward a rotating direction of the mirror holder. Therefore, when the sliding portion slides on the protruding portions, foreign matter is easily ejected from between the sliding portion and the protruding portions to sideward of the protruding portions, and foreign matter can be effectively ejected from between the sliding portion and the protruding portions. Therefore, the sliding portion can slide smoothly against the protruding portions, and the rotating of the mirror holder can be made stable.