PURPOSE: To prevent damage of parts by preparing locking means fixing a mirror in a home position when a power source is not inputted to a rocking morror driver.

CONSTITUTION: When a power source is applied to an are motor 5, an electromagnt 14 and a solenoid 22, a moveable member 23 is drawn in against a coil spring 21, allowing a locking lever 17 to be pulled rearward and an arm 4 and a lever 17 to be disconnected. The arm 4 becomes therefore rotatable between the electromagnet 14 and a stator 6 and reciprocates between a home position H and a return position R. When a power source turns off, a rocking member is actuated to the H side based on the center of gravity, allowing the atm 4 to contact with the electromagnet 14 to become stationary. On the other hand, with restoring force of the coil spring 21, the locking lever 17 is rotated to engage with the arm 4. Through the process, damage of parts during transportation is prevented.