A hot water supply device comprising: a heating device (1, 51) that heats hot or cold water; a circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) configured to include a channel for hot or cold water provided in the heating device (1, 51), and capable of circulating hot or cold water through the heating device (1, 51); a circulation device (12, 55) that uses the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) to circulate hot or cold water through the heating device (1, 51); and a control device that controls the heating device (1, 51) and the circulation device (12, 55), uses the circulation device (12, 55) to circulate hot or cold water through the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55), and performs a heating operation for heating the hot or cold water with the heating device (1, 51), wherein when performing the heating operation, the control device controls the circulation device (12, 55) to perform a steady operation for maintaining a circulation flow rate of hot or cold water flowing through the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) at a preset steady flow rate, and a pulsing operation for temporarily increasing and reducing the circulation flow rate with respect to the steady flow rate, and maintains a flow rate difference between a maximum value and a minimum value of the circulation flow rate during the pulsing operation at a reference value or larger at which deposition of alien substance in the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) can be prevented, characterized in that the maximum value of the circulation flow rate is higher than the steady flow rate, and the minimum value of the circulation flow rate is lower than the steady flow rate. a heating device (1, 51) that heats hot or cold water; a circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) configured to include a channel for hot or cold water provided in the heating device (1, 51), and capable of circulating hot or cold water through the heating device (1, 51); a circulation device (12, 55) that uses the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) to circulate hot or cold water through the heating device (1, 51); and a control device that controls the heating device (1, 51) and the circulation device (12, 55), uses the circulation device (12, 55) to circulate hot or cold water through the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55), and performs a heating operation for heating the hot or cold water with the heating device (1, 51), wherein when performing the heating operation, the control device controls the circulation device (12, 55) to perform a steady operation for maintaining a circulation flow rate of hot or cold water flowing through the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) at a preset steady flow rate, and a pulsing operation for temporarily increasing and reducing the circulation flow rate with respect to the steady flow rate, and maintains a flow rate difference between a maximum value and a minimum value of the circulation flow rate during the pulsing operation at a reference value or larger at which deposition of alien substance in the circulation circuit (3A, 12, 13, 23, 24, 25, 51B, 54, 55) can be prevented, characterized in that the maximum value of the circulation flow rate is higher than the steady flow rate, and the minimum value of the circulation flow rate is lower than the steady flow rate.