PURPOSE: To avoid occurrence of an abnormal pressure in a heat pump using a vapor liquid separator by providing means for arranging a subcooler for cooling liquid phase refrigerant to be fed from the separator to expansion means on an upstream side of a liquid receiver.

CONSTITUTION: A vapor liquid separator Sp in an indoor unit Ui separates high pressure refrigerant Rwg to be supplied from a high pressure refrigerant output unit A of an outdoor unit Uo to vapor phase refrigerant Rg and liquid phase refrigerant Rww. A warm heat generating condenser Ci condenses the refrigerant Rg. Further, cold generating evaporator Ei passes the refrigerant Rww to expansion means exp, and then evaporates it. In such a heat pump, a liquid receiver T is arranged in a passage rw for guiding the refrigerant Rww to the means exp. Further, a subcooler Coo for cooling the refrigerant Rww to be fed from the separator Sp to the means exp on an upstream side of the receiver T is arranged. In addition, regulating means X for regulating a cooling amount of the subcooler Coo is arranged.