PURPOSE: To maintain the rear visual range of a mirror always good by fixing the mirror body of the side mirror for a car at the end of the revolution shaft of a motor and removing the water droplet adhered on the surface of the mirror body by revolving the mirror body.

CONSTITUTION: The mirror body 2 of a side mirror is made circular and the center part is fixed at the end of the revolution shaft of a DC motor 1. The DC motor 1 is fixed inside a casing by a fixing equipment 3 and connected electrically with a battery 6 through wiring cords 4. When a car travels in rainy weather, if water droplets adheres on the surface of the mirror body 2 and the rear visual range becomes poor, a switch 5 is turned on, and the DC motor 1 is driven, and the mirror body 2 is revolved at high speed. Then, the water droplets adhered on the surface of the mirror body 2 are springed-out by a centrifugal force, and good visual range can be obtained.