To effectively and accurately detect foreign objects caught by a power window according to fluctuation in a load on a motor by providing a driving sensor, which outputs speed signals corresponding to the driving speed of a vehicle and a means for varying overload value, based on the signals from the driving sensor.

According to the length of the cycle of traveling pulses from a driving sensor 13, the resistance value of a reference resistance circuit portion 7 connected with the reference resistance connecting terminal T4 of IC 5 for load power supply control is varied through a trigger circuit portion 9 by switching between a combined resistance of reference resistors Rr and Rr3 and a combined resistance of reference resistors Rr1 and Rr3 which is higher than the former combined resistance. The overcurrent determining value associated with a motor 3 set by the resistance value of the reference resistance circuit portion 7 is varied. For this reason, even if frictional force acting on the window when the window is opened and closed is increased so that the load on the motor 3 is increased, the determined value of the overcurrent associated with the motor 3 is revised upward and power supply from a battery 1 to the motor 3 is prevented from stopping.