A heat pump-type hot water supply apparatus, comprising: a refrigeration cycle circuit including a compressor, an outdoor heat exchanger, expansion devices (16 and 17), and an indoor heat exchanger in which a first refrigerant is circulated and performing an air-conditioning operation; a hot water supply heat exchanger connected to the refrigeration cycle circuit to use the first refrigerant discharged from the compressor for hot water supply; a cascade heat exchanger disposed downstream of the hot water supply heat exchanger and connected to the refrigeration cycle circuit to allow the first refrigerant passing through the hot water supply heat exchanger to evaporate a second refrigerant and thereafter, to be condensed, expanded, and evaporated in the refrigeration cycle circuit; a heat storage compressor compressing the second refrigerant evaporated in the cascade heat exchanger; a heat storage tank in which the second refrigerant discharged from the heat storage compressor heats water to store heat of the second refrigerant in the water therein; a heat storage expansion device expanding the second refrigerant condensed in the heat storage tank; a water and refrigerant heat exchanger connected between the hot water supply heat exchanger and the cascade heat exchanger through a water and refrigerant heat exchanger connection path; a water and refrigerant heat exchanger refrigerant controller controlling the flow of the first refrigerant to allow the first refrigerant passing through the hot water supply heat exchanger to pass through or bypass the water and refrigerant heat exchanger; a floor heating pipe connected to the water and refrigerant heat exchanger through a heating circulation path; and a floor heating pump installed on the heating circulation path, wherein the heat storage tank is connected to the hot water supply heat exchanger through a hot water supply circulation path or is connected to the water and refrigerant heat exchanger through the heating circulation path to store heat of the first refrigerant in the water therein. a refrigeration cycle circuit including a compressor, an outdoor heat exchanger, expansion devices (16 and 17), and an indoor heat exchanger in which a first refrigerant is circulated and performing an air-conditioning operation; a hot water supply heat exchanger connected to the refrigeration cycle circuit to use the first refrigerant discharged from the compressor for hot water supply; a cascade heat exchanger disposed downstream of the hot water supply heat exchanger and connected to the refrigeration cycle circuit to allow the first refrigerant passing through the hot water supply heat exchanger to evaporate a second refrigerant and thereafter, to be condensed, expanded, and evaporated in the refrigeration cycle circuit; a heat storage compressor compressing the second refrigerant evaporated in the cascade heat exchanger; a heat storage tank in which the second refrigerant discharged from the heat storage compressor heats water to store heat of the second refrigerant in the water therein; a heat storage expansion device expanding the second refrigerant condensed in the heat storage tank; a water and refrigerant heat exchanger connected between the hot water supply heat exchanger and the cascade heat exchanger through a water and refrigerant heat exchanger connection path; a water and refrigerant heat exchanger refrigerant controller controlling the flow of the first refrigerant to allow the first refrigerant passing through the hot water supply heat exchanger to pass through or bypass the water and refrigerant heat exchanger; a floor heating pipe connected to the water and refrigerant heat exchanger through a heating circulation path; and a floor heating pump installed on the heating circulation path, wherein the heat storage tank is connected to the hot water supply heat exchanger through a hot water supply circulation path or is connected to the water and refrigerant heat exchanger through the heating circulation path to store heat of the first refrigerant in the water therein.