A control unit, at the time of a heating operation, pressure-reduces refrigerant that has passed through an indoor condenser, by an expansion valve, and thereafter introduces the refrigerant into an outdoor heat exchanger to thereby perform heat exchange with outside air. Further, the control unit, at the time of a defrosting operation, introduces high-temperature and high-pressure refrigerant compressed by a compressor into the outdoor heat exchanger to thereby remove frost adhering to the outdoor heat exchanger. Furthermore, the control unit determines whether to perform the defrosting operation or not, based on the amount of electric power required for the defrosting operation.