A heat pump water heating system comprising: a first circulation circuit including a heat pump unit and a first circulation pump; a second circulation circuit including a second heat source having a higher temperature than the heat pump unit, and a second circulation pump; a third circulation circuit including a mixing tank that connects the first circulation circuit and the second circulation circuit, and a third circulation pump; a fourth circulation circuit including a hot water storage tank that stores tank water, and a fourth circulation pump; a heat exchanger that exchanges heat between water flowing through the third circulation circuit, and the tank water flowing through the fourth circulation circuit; a controller being configured to control the first circulation pump, the second circulation pump, the third circulation pump, and the fourth circulation pump, characterized by a temperature sensor that detects a temperature of the tank water within the hot water storage tank; and the controller being configured to control the first circulation pump, the second circulation pump, the third circulation pump, and the fourth circulation pump such that if the temperature of the tank water detected from the temperature sensor is lower than a first preset temperature, the controller drives the first circulation pump, the third circulation pump, and the fourth circulation pump, and uses the heat pump unit to increase the temperature of the tank water within the hot water storage tank via the heat exchanger, and if the temperature of the tank water detected from the temperature sensor is equal to or higher than the first preset temperature, the controller stops the first circulation pump, drives the second circulation pump, the third circulation pump, and the fourth circulation pump, and uses the second heat source to increase the temperature of the tank water within the hot water storage tank via the heat exchanger in a shorter time than that of a case in which the heat pump unit is used to increase the temperature. a first circulation circuit including a heat pump unit and a first circulation pump; a second circulation circuit including a second heat source having a higher temperature than the heat pump unit, and a second circulation pump; a third circulation circuit including a mixing tank that connects the first circulation circuit and the second circulation circuit, and a third circulation pump; a fourth circulation circuit including a hot water storage tank that stores tank water, and a fourth circulation pump; a heat exchanger that exchanges heat between water flowing through the third circulation circuit, and the tank water flowing through the fourth circulation circuit; a controller being configured to control the first circulation pump, the second circulation pump, the third circulation pump, and the fourth circulation pump, characterized by a temperature sensor that detects a temperature of the tank water within the hot water storage tank; and the controller being configured to control the first circulation pump, the second circulation pump, the third circulation pump, and the fourth circulation pump such that if the temperature of the tank water detected from the temperature sensor is lower than a first preset temperature, the controller drives the first circulation pump, the third circulation pump, and the fourth circulation pump, and uses the heat pump unit to increase the temperature of the tank water within the hot water storage tank via the heat exchanger, and if the temperature of the tank water detected from the temperature sensor is equal to or higher than the first preset temperature, the controller stops the first circulation pump, drives the second circulation pump, the third circulation pump, and the fourth circulation pump, and uses the second heat source to increase the temperature of the tank water within the hot water storage tank via the heat exchanger in a shorter time than that of a case in which the heat pump unit is used to increase the temperature.