PURPOSE: To reduce power consumption by interrupting delivery of an operational signal from an integration control system when a motor is in a stop state thereby interrupting delivery of driving power from a drive control system.

CONSTITUTION: A difference circuit 10 determines the difference between a target position signal C(t) from a central control means 9 and a feedback signal E(t) from an encoder circuit 11 and delivers an error signal e(t) to a proportional control system A, an integration control system B and a differentiation control system C. Subsequently, a PWM circuit 23 outputs a PWM signal PWM(t) having a duty corresponding to the sum of operational signals R(t), I(t) and D(t) and a drive circuit E delivers a power amplified power signal P(t) to a motor M thus controlling the driving thereof. When the motor M stops, a central control means 9 interrupts a limiter circuit 15 in the integration control system B based on a control signal RS and generates the PWM signal PWM(t) and the power signal P(t) in order to nullify the operational signal I(t). This constitution reduces power consumption under a state where the motor is stopped.