A PWM control part rotationally drives a motor based on a PWM control value. A rotation speed control part controls a rotation speed of the motor. A rotation angle detection part detects a rotation angle of the motor. A reference position learning part controls the motor to rotate at a constant rotation speed until a detent plate stops at a limit position of a movable range and learns a reference position of the motor. A current detection circuit detects a current value corresponding to a driving current. A current limitation part limits a current supplied to the motor. A PWM control value limitation part controls the PMW control value to be equal to or smaller than a PWM limitation value, which is a predetermined value. A relation check part checks whether a relation between a current value detected by the current detection circuit and the PWM control value is inappropriate.