PURPOSE: To provide a control valve that promotes simplification in a valve mechanism and improvement in control responsiveness, etc.

CONSTITUTION: An ultrasonic motor USM is set up in an outer circumferential part of a flow passage pipe 5, while a rotary plate 3 with an opening in this flow passage pipe 5 is rotatably set up in a fixed plate 4 with an opening, and a rotor 1 of the ultrasonic motor USM is locked to the rotary plate 3. The rotary plate 3 is directly 1 rotated and driven by the rotor 1 rotating by means of drive of this motor USM, thereby controlling a flow rate or the like.