An ultrasonic motor has a piezoelectric element driven by application of a voltage thereto to undergo expansion and contraction. A vibrating body is vibrationally driven by the expansion and contraction movement of the piezoelectric element to thereby produce standing waves. A moving body is frictionally driven by the standing waves of the vibrating body. Power transmission projections apply a frictional force to the moving body to thereby frictionally drive the moving body in accordance with the standing waves. The power transmission projections are disposed only every preselected number of wavelengths at intermediate positions between loops and nodes of the standing waves, the preselected number being a natural number.