A heat pump hot-water supply device includes: a tank; a refrigerant circuit having a water heat exchanger; water conduits; an electrolysis device having an electrode pair provided in a water channel upstream of the water heat exchanger, in a flow channel of water that includes the water conduits; and a control unit that executes a reversal initial operation of reversing the polarity of the electrode pair in the electrolysis device, and discharging, at a position upstream of the water heat exchanger, water that is treated in the electrolysis device during a period after polarity reversal until a predetermined condition is satisfied.