A cylindrical piezoelectric element is arranged to share an axis with a cylindrical vibrator having different diameters at central and end portions to fix the vibrator forming a gap at the central portion. Vibration voltages are applied across first electrodes on the piezoelectric element and the vibrator, namely, a second electrode, to vibrate the vibrator and bring a wave front of a traveling wave into contact with a tubular member, i.e., a supporting member fitted to the vibrator. Friction at a contact portion of the vibrator moves a mover including the vibrator and the piezoelectric element in an axial direction of the tubular member. By amplifying the vibration amplitude using the vibrator provided separately from the piezoelectric element, a small actuator capable of performing high-speed driving is realized.