A hot water supply device with a heat pump, comprising: a main refrigerant circuit including a compressor compressing refrigerant, an expander, and a first water-refrigerant heat exchanger in which heat is exchanged between the refrigerant and water supplied from a water supply source; a heating/cooling part including an air-conditioning heat exchanger through which circulation water circulates; a hot water supply part including a hot water supply heat exchanger in which heat is exchanged between the water supplied from the water supply source and the circulation water; a second water-refrigerant heat exchanger in which heat is exchanged between the refrigerant and circulation water, and wherein the hot water supply device further comprises: a three-way valve switching a flow direction of the circulation water passing through the second water-refrigerant heat exchanger to the hot water supply part or the heating/cooling part; a water supply passage to receive water from the water supply source; a hot water supply side passage connecting the water supply passage to the hot water supply part to supply water from the water supply source to the hot water supply part; a circulation passage in which water to be heat-exchanged with the refrigerant in the first water-refrigerant heat exchanger circulates; a circulation side supply passage connected to the water supply passage and extending to the circulation passage so as to supply the water in the water supply passage to the circulation passage; and a water supply adjustment part installed on the circulation side supply passage to selectively prevent a water supply through the circulation side supply passage, and wherein the refrigerant flowing through the second water-refrigerant heat exchanger and the first water-refigerant heat exchanger are heat-exchanged with water, and wherein the main refrigerant circuit further comprises a flow switch part switching a flow direction of a refrigerant discharged from the compressor to one of the first and the second water-refrigerant heat exchanger (14, 12). a main refrigerant circuit including a compressor compressing refrigerant, an expander, and a first water-refrigerant heat exchanger in which heat is exchanged between the refrigerant and water supplied from a water supply source; a heating/cooling part including an air-conditioning heat exchanger through which circulation water circulates; a hot water supply part including a hot water supply heat exchanger in which heat is exchanged between the water supplied from the water supply source and the circulation water; a second water-refrigerant heat exchanger in which heat is exchanged between the refrigerant and circulation water, and wherein the hot water supply device further comprises: a three-way valve switching a flow direction of the circulation water passing through the second water-refrigerant heat exchanger to the hot water supply part or the heating/cooling part; a water supply passage to receive water from the water supply source; a hot water supply side passage connecting the water supply passage to the hot water supply part to supply water from the water supply source to the hot water supply part; a circulation passage in which water to be heat-exchanged with the refrigerant in the first water-refrigerant heat exchanger circulates; a circulation side supply passage connected to the water supply passage and extending to the circulation passage so as to supply the water in the water supply passage to the circulation passage; and a water supply adjustment part installed on the circulation side supply passage to selectively prevent a water supply through the circulation side supply passage, and wherein the refrigerant flowing through the second water-refrigerant heat exchanger and the first water-refigerant heat exchanger are heat-exchanged with water, and wherein the main refrigerant circuit further comprises a flow switch part switching a flow direction of a refrigerant discharged from the compressor to one of the first and the second water-refrigerant heat exchanger (14, 12).