Abstract: The present invention relates to a control device for an auxiliary member of vehicles which is capable of suspending the driving of the auxiliary member of a vehicle such as a compressor for air conditioning device when there is a sudden increase of the load on the driving system of the vehicle and which is also capable of driving the auxiliary member as much as possible when the engine is operating below its maximum capacity. The control device comprises a means to detect the load of the driving system of a vehicle and the rate of acceleration of said load, a means to control the driving of an auxiliary member which is driven by the engine of the vehicle, and a means to transmit a signal to the driving mechanism of said auxiliary member to suspend its driving from the time when the acceleration of the load of the driving system of the vehicle exceeds a predetermined value until the time when the load returns to the predetermined value.