<p>An actuator suitable for use in a joint device for driving a robot arm or in a subject follow-up device in a video camera, etc. is designed to have a mobility of a freedom of two degrees or more and is adapted to drive a movable part directly using first piezoelectric motor elements each of which consists of piezoelectric elements (8a) having a non-ring-like configuration and an elastic body (9) and second piezoelectric motor elements (8b) each of which consists of at most one ring-like piezoelectric element and an elastic member. The actuator exhibits a simplified structure, is small and lightweight, provides a powerful driving power and has a wide range of mobility.</p>
