There is provided a heat pump apparatus bringing heating water to a high temperature by connecting one or a plurality of load-side units to one heat source-side unit. The air conditioning-hot water supply combined system (heat pump apparatus) includes a heat source-side unit equipped with an air conditioning compressor, a four-way valve, and an outdoor heat exchanger; and the load-side units equipped with an air conditioning throttle, an indoor heat exchanger, a second compressor, a second load-side heat exchanger, and a second flow rate control unit. Here, a main circuit is configured by sequentially connecting the air conditioning compressor, the four-way valve, the outdoor heat exchanger, the air conditioning throttle, and the indoor heat exchanger, using a high-pressure side connection piping and a low-pressure side connection piping. On the other hand, a load-side refrigerant circuit is configured by sequentially connecting the second compressor, a second load-side heat exchanger second load-side heat exchanger, the second flow rate control unit, and the indoor heat exchanger using a load-side refrigerant piping.