To enhance the performance of an oscillatory actuator by making the speed range adjustable over a wide range from low speed region to high speed region.

The actuator driver comprises a power supply means for applying alternating signals having a different phase to the two-phase exciting source of an oscillatory actuator in order to generate an elliptical motion in a resilient member. The power supply means comprises means for adjusting the drive frequency and means for regulating the phase difference of the applying voltage which are switches (S106, S107) depending on the drive speed.