PURPOSE: To remove the transfer loss of oscillation by providing movement components in the direction of rotation directly in an elastic body forming a rotor.

CONSTITUTION: An ultrasonic motor is constituted of an elastic moving member 1, a piezo-electric element 3 to rotate the moving member, an elastic body 2, an elastic plate section 4, a spring section 6, a motor shaft and so on. The piezo-electric element 3 rotates together with the elastic moving member 1, and a piezo-electric element 3' is secured to make a stator. Accordingly, when the elastic moving member 1 is oscillated by the piezo-electric element 3, the elastic plate section 4 provided in the moving substance 1 is bent and the oscillation is converted into an expansion movement direction in the direction of rotation. Inherent oscillation frequency of the expansion movement in the direction of rotation of the moving substance 1 is almost matched with that of the expansion movement of the other piezo-electric element 3', and the force of a forward rotation of a reverse rotation is continuously taken out.