A motor driving unit controls motor conducted current of a brushed DC motor on the basis of a motor control signal. A motor control unit provides the motor control signal to the motor driving unit and thereby controls the brushed DC motor. A brush noise detecting unit detects brush noises in conducted current of the brushed DC motor and outputs a brush noise detection signal. A speed determining unit determines a time interval of the brush noises and determines a rotation speed of the brushed DC motor on the basis of the time interval. Further, the motor control unit determines whether the brushed DC motor is in a lock status or not on the basis of the rotation speed in a period that the motor control signal is provided to the motor driving unit to cause the brushed DC motor to be in operation.