A new type of rotary motor by inchworm motion using two belts is developed. A rotor is wrapped by two opposite belts which are connected to piezoelectric actuators. A serial lever structure with flexure hinges is used to connect a belt and piezoelectric actuators. The lever structure amplifies micro displacement of a piezoelectric actuator. A rotational motion with the step size of 2.36 mu rad is obtained through this work. An angular step size can be further reduced by increasing the rotor radius. We present a analysis model of the motor for a design of a similar precise motor. (C) 1999 American Institute of Physics. [S0034-6748(99)04004-6].