We succeeded in developing an ultrasonic micro-motor with a diameter of 4.5mm and a thickness of 2.5mm.This motor uses the standing wave method so we can drive it by only a one-phase electrical signal in two directions.Therefore we can construct a self-oscillating drive circuit easily.This motor has a very hight torque(the starting torque:0.27gfcm at DC 2.8V).We applied this motor to a calendar mechanism in a watch and succeeded in miniaturizing and simplifying the mechanism bacause of the volume and the torque of the ultrasonic micro-motor.