PURPOSE: To provide the lens actuator which improves the sliding of a bearing and can exhibit performance even in an axial horizontal posture as the lens actuator to be used for optical and magneto-optical devices, etc.

CONSTITUTION: A piezoelectric vibrator 9 is mounted to the end face of a shaft or a base fixed with the shaft 2 and is vibrated at 50 to 400kHz, by which the bearing is put into a half floating state. The lens actuator which improves the sliding of the bearing and maintains the performance without changing with a difference in posture is obtd.