Abstract: In order to provide a mechanism for driving a screw rod by supersonic vibrations, which may achieve space savings, prevent back-lash of a work rack, and effect smooth operation, a first screw rod rotation device is provided for rotation of a screw rod in a first direction, and a second screw rod rotation device is provided for rotation of the screw rod in a second direction. The first screw rod rotation device includes a first vibrator contacting a groove portion of the screw rod at a specific angle, a first spring urging the first vibrator toward the groove portion of a screw rod at a specific pressure and a first piezoelectric actuator for vibrating the first vibrator upon electrical activation.