PURPOSE:To obtain a highly efficient ultrasonic motor which operates stably at all times by sustaining uniform contact between an oscillator and a mover while solving a problem that the oscillation of the oscillator is disturbed by the machining accuracy of component or fluctuation of external load and not transmitted efficiently to the mover thus deteriorating efficiency and stability. CONSTITUTION:A rotary shaft is passed through a small hole made in the center of a mover 13 and a spring structure is constituted at the joint of the rotary shaft 18 and the mover 13 as well as the contacting part of the mover 13 and an oscillator 12. Frictional force between the spring part of the rotary shaft 18 and the mover 13 is set higher than that between the mover 13 and the oscillator 12.
