To prevent, with a low-cost configuration, a DC motor from rotating due to environmental changes, measurement error, individual difference of circuit elements, or the like, even if control instructions for stopping the DC motor are outputted.

A motor driving part including DC motors 102 and 121 is so configured that the DC motor rotates, when a motor current flows in normal direction, while rotation of the DC motor stops when it flows in the opposite direction. A current control signal Vo, which determines direction and quantity of the motor current, is outputted from a current control part 200 to a motor driver 141. The current control part contains an analogue circuit and outputs the current control signal Vo, to allow the motor current in the direction opposite to the normal direction to flow to the DC motor, when a controller 150 outputs the command instruction for stopping the DC motor.