When half depression of a camera key is detected, a narrow pulse voltage is applied to a piezoelectric element such that the AF gear meshes with a gear provided on the lens frame. Then, a wide pulse voltage opposite in polarity is applied to the piezoelectric element such that the AF gear moves away from the gear provided on the lens frame with the AF gear meshing with a drive gear of the AF motor, and then meshes with a shutter gear. Rotation of the drive gear of the AF motor is transmitted to the AF gear and the gear provided on the lens frame while turning the shutter blade.