To increase a resultant torque and to stabilize revolution, an electro-mechanical energy conversion device (14) is fixed to a position at which a stepped circular cylindrical flexible member (13) equipped with fastening portions (13c, 13d) between fixed portions (13a, 13b) at both ends is fixed, in an ultrasonic motor of the present invention. When an A.C. voltage having a phase difference is applied to this electro-mechanical energy conversion device (14), a plurality of vibration modes are generated. A pair of circular cylindrical flexible members (11, 12) for clamping the electro-mechanical energy conversion device (14) are fixed to the stepped circular cylindrical flexible member (13). Accordingly, rotating oscillation or elliptic oscillation occurs at free ends (11b, 12b) of the circular cylindrical flexible members (11, 12). A driving roller which is brought into pressure contact with these free ends (11b, 12b) is caused to rotate due to rotating oscillation or elliptic oscillation. The force applied to the circular cylindrical flexible members (11, 12) is received by the electro-mechanical energy conversion device (14).