To improve a force for holding the inner mirror by a base.

A base 4 holding a base inner 6 for holding an inner mirror 2 is constituted by a first base 30 bonded to a front window 3 and a second base 40 clasped by the base inner 6. The second base 40 is provided with a recessed fitting part 43 into which the first base 30 is fitted, and wider parts 41a, 41b brought into contact with side faces 33a, 33b of the first base 30 and extending outward from the side faces 33a, 33b of the first base 30. When the first base 30 is fitted into the fitting part 43 of the second base 40, the fitting width of the base 4 fitted with the base inner 6 can be expanded by the width of the wider parts 41a, 41b of the second base 40. Therefore, the force for holding the inner mirror 2 by the base 4 can be improved even if the first base 30 is commoditized.