The present invention aims to provide a compact and lightweight
piezoelectric actuator, a driving method involving the piezoelectric
actuator that can provide a large displacement at a low voltage, and a
compact and lightweight information storage device with a high recording
density that incorporates such a piezoelectric actuator and has a small
moment of inertia of a head when the head is driven. The piezoelectric
actuator according to the present invention has four rod-shaped driving
sections. Of the four rod-shaped driving sections, a voltage is applied to
the two driving sections located along a diagonal line at a time, and the
voltage is applied to the two driving sections located along the other
diagonal line at a different time from the time for the first two driving
sections, whereby two central sections are rotationally driven relative to
two end sections.
