A vehicular air conditioning system capable of suppressing the power consumption of a refrigerating cycle is disclosed. The vehicular air conditioning system comprises a refrigerating cycle circuit comprising a compressor, an outside heat exchanger and an inside air conditioning heat exchanger annularly connected in order, and a device cooling circuit comprising a heating unit, an inside cooling heat exchanger, an intermediate heat exchanger and a pump being annularly connected, the intermediate heat exchanger being constructed such that one end of a piping of the cooling medium for air conditioning is connected to a liquid piping, the liquid piping providing connection between the outside heat exchanger and the inside air conditioning heat exchanger, and an opposite end of the piping of the cooling medium for air conditioning is connected to a suction port of the compressor.