PURPOSE: To drive an optical system without mechanical vibration by fixing a magnet to an optical system holder and providing a magnetic body which faces the magnet nearly in parallel to a guide shaft.

CONSTITUTION: Angular moment operates on the holder 1 by the attracting force between a magnet 9 and a magnetic body 11 and the attracting force between a magnet 10 and a magnetic body 12, and the holder 1 slants by θ2 to the guide shaft 6. This angle θ2 of inclination is held almost constant even when the holder 1 is moved to left or right in the figure because the angular moment operates all the time. Namely, the holder 1 has almost none of vibration originating from the friction between bearings 3 and 4 and guide shaft 6 and other external factors. Therefore, a mirror 2 has no mechanical vibration and there is no unevenness of scanning.