VEHICLE AIR CONDITIONING DEVICE

There is disclosed a vehicle air conditioning device of a heat pump system which delays proceeding of frosting onto an outdoor heat exchanger, thereby eliminating or inhibiting deterioration of a heating capability due to the frosting. The vehicle air conditioning device executes a heating mode in which a controller lets a refrigerant discharged from a compressor radiate heat in a radiator decompresses the refrigerant by which heat has been radiated, and then lets the refrigerant absorb heat in an outdoor heat exchanger and on the basis of a difference TXO=(TXObase−TXO) between a refrigerant evaporation temperature TXObase of the outdoor heat exchanger in non-frosting and a refrigerant evaporation temperature TXO of the outdoor heat exchanger the controller corrects a target subcool degree TGSC that is a target value of a subcool degree of the refrigerant in the radiator in an increasing direction in accordance with increase of the difference ΔTXO.