PURPOSE: To reduce noise and vibration and improve durability by securing a magnet piece fixedly to an end of an actuator bar projecting from an elastic body and disposing a rotary magnet opposed to the magnet piece.

CONSTITUTION: One end of an actuator bar 11 is attached by a screw to the upper surface of a cap 22 of a vacuum pump K and the other end is bent downward to be secured fixedly to a magnet piece 12 on the end face, a rotary magnet 13 being disposed opposed to the magnet piece 12. Thus, the actuator bar 11 can be driven by the rotation of rotary magnet 13 without any mechanical contact so that noise and vibration can be reduced and durability can be improved by the absence of parts to be worn out.