PURPOSE: To prevent the damage of a motor by providing such a constitution as to immediately reverse a motor when a motor control part judges that motor current is of an abnormal level on the basis of the output of a current detecting part.

CONSTITUTION: When a door 30 approaches a vehicle body 100 at the time of closing the door 30, a power supply switch 85 detects this and outputs a power source supply command signal to operate the power rely 6 of a power control unit 1. When the door 30 comes closer to the vehicle body 100, a power source is supplied to a full-lock control unit 2, and a motor 41 is positively rotated. When an overcurrent is sent to the motor 41 because a foreign material is entered between the door 30 and the vehicle body 100, the second current level detecting circuit 14B of a current detecting part 8 detects this and outputs a high level signal. Further, a motor control circuit 15 forcedly reverses the motor 41 through a motor switching circuit 16.