HOT WATER SUPPLY DEVICE

A flow rate of hot or cold water flowing through a circulation circuit is appropriately changed to prevent deposition of alien substance such as scale, and stably perform a heating operation. A hot water supply device includes a heat pump unit 1, a hot water storage tank 11, a circulation pump 12, a control device 30, or the like. When performing the heating operation, the control device 30 controls a rotation speed of the circulation pump 12 to perform a steady operation for maintaining a circulation flow rate of hot or cold water flowing through a secondary channel 3A of the water heating heat exchanger 3 at a steady flow rate A, and a pulsing operation for temporarily reducing and increasing the circulation flow rate with respect to the steady flow rate A. Also, a flow rate difference ”A between a maximum flow rate A H and a minimum flow rate A L of the circulation flow rate during the pulsing operation is maintained at a reference value S or larger at which deposition of alien substance in the secondary channel 3A can be prevented. Thus, the heating operation can be stably performed, and pulsing of the circulation flow rate can be used to prevent deposition of scale.