Abstract: An operating control device for an air conditioner for use in a vehicle comprises a temperature sensor for sensing the temperature of a fuel supplied into the engine, and a detector switch for detecting deep depression of an accelerator pedal. The operating control device further comprises an operating control circuit comprising a first relay circuit operative when the fuel temperature sensed by the temperature sensor is above a predetermined value, and a second relay circuit operative when the first relay circuit is activated and when it is detected by said detector means that the accelerator pedal has been deeply depressed to interrupt a power supply circuit including the compressor, thereby enabling to securely detect an increase in an engine load during a driving on an ascending load surface to interrupt the operation of the compressor to attain sufficient vehicle drive performance.