A heat pump water heater comprising; a first heat pump cycle in which carbon dioxide gas refrigerant circulates through at least a compressor and an expander, a second heat pump cycle in which HFC refrigerant circulates through at least a compressor and an expander, and a water heat exchanger for conducting heat exchange between water and the carbon dioxide gas refrigerant and the HFC refrigerant, and a storage tank for storing hot water heater in the water heat exchanger, characterized in that, the second heat pump cycle including a first circulation path having piping passing through first and second switching valves (41, 42, 51, 54), and the water heat exchanger, wherein the first and second switching valves (41, 42, 51, 54) are operable to switch between the first circulation path and a second circulation path, the second circulation path passing through first and second switching valves (41, 42, 51, 54), an indoor air heat exchanger for conducting heat exchange between the HFC refrigerant and indoor air, and an outdoor air heat exchanger, and circulating direction switching means for switching the circulation direction of the HFC refrigerant in the second heat pump cycle, a third switching valve for directing water flow from the heat exchanger to either the storage tank or a hot water supply, a fourth switching valve for directing water from the storage tank or a water supply port to the hot water supply, a fifth switching valve for directing water from either the water supply port or the storage tank to the heat exchanger, a first water flowing path between a water supply port and the hot water supply via the storage tank, a circulation pump, the fifth switching valve, heat exchanger, and the third switching valve, a second water flowing path between the water supply port and to a hot water supply port via the fifth switching valve, heat exchanger, and the third switching valve, a third water flowing path between the storage tank and the hot water supply port via the fourth switching valve, a fourth water flowing path between the water supply port and the hot water supply via the fourth switching valve, and said heat pump water heater operable to conduct: a hot water storage operation, distributing water along the first water path, for storing hot water that has been heated by the carbon dioxide gas refrigerant in the water heat exchanger by circulating the carbon dioxide gas refrigerant in the first heat pump cycle, in the storage tank, an instantaneous hot water supply operation, distributing water supplied along the second water path, for directly outputting the hot water heated by the HFC refrigerant in the piping through the water heat exchanger to a hot water supply port not via the storage tank, by circulating the HFC refrigerant in the first circulation path, in the second heat pump cycle, and cooling and heating operations for heating or cooling indoor air by the HFC refrigerant in the indoor air heat exchanger by circulating the HFC refrigerant in the second circulation path in the second heat pump cycle, wherein the circulating direction switching means circulates the HFC refrigerant in a first direction during the cooling operation and in a second direction during the heating operation, wherein the HFC refrigerant circulating in the second heat pump cycle can be distributed to the first and the second circulation paths (20, 40) for circulation when there occurs a request for the instantaneous hot water supply operation during the process of heating or cooling operation. a hot water storage operation, distributing water along the first water path, for storing hot water that has been heated by the carbon dioxide gas refrigerant in the water heat exchanger by circulating the carbon dioxide gas refrigerant in the first heat pump cycle, in the storage tank, an instantaneous hot water supply operation, distributing water supplied along the second water path, for directly outputting the hot water heated by the HFC refrigerant in the piping through the water heat exchanger to a hot water supply port not via the storage tank, by circulating the HFC refrigerant in the first circulation path, in the second heat pump cycle, and cooling and heating operations for heating or cooling indoor air by the HFC refrigerant in the indoor air heat exchanger by circulating the HFC refrigerant in the second circulation path in the second heat pump cycle, wherein the circulating direction switching means circulates the HFC refrigerant in a first direction during the cooling operation and in a second direction during the heating operation,