A heat pump hot-water supply device, comprising: a first refrigerant cycle, in which a first refrigerant circulates, and including a first compressor, an outdoor heat exchanger, and a first expansion device; a second refrigerant cycle, in which a second refrigerant circulates, and including a second compressor and a second expansion device; a water-refrigerant heat exchanger, to which the first refrigerant compressed in the first compressor and the second refrigerant compressed in the second compressor is introduced; a water introduction path coupled to a first side of the water-refrigerant heat exchanger and into which supplied water is introduced; and a water discharge path coupled to a second side of the water-refrigerant heat exchanger and from which the water heat-exchanged in the water-refrigerant heat exchanger is discharged, the water-refrigerant heat exchanger includes: a first inflow that guides introduction of the first refrigerant; and a first outflow from which the first refrigerant introduced through the first inflow and heat-exchanged is discharged; a second inflow that guides introduction of the second refrigerant compressed in the second compressor; and a second outflow from which the second refrigerant introduced through the second inflow and heat-exchanged is discharged, the heat pump hot-water supply device further includes a guide tube that allows the second refrigerant discharged from the second outflow to be re-introduced into the water-refrigerant heat exchanger, the second expansion device being provided on the guide tube; characterized in that the heat pump hot water supply device further includes a bypass tube divided from the guide tube to extend to the outdoor heat exchanger; and a bypass valve provided in the bypass tube. a first refrigerant cycle, in which a first refrigerant circulates, and including a first compressor, an outdoor heat exchanger, and a first expansion device; a second refrigerant cycle, in which a second refrigerant circulates, and including a second compressor and a second expansion device; a water-refrigerant heat exchanger, to which the first refrigerant compressed in the first compressor and the second refrigerant compressed in the second compressor is introduced; a water introduction path coupled to a first side of the water-refrigerant heat exchanger and into which supplied water is introduced; and a water discharge path coupled to a second side of the water-refrigerant heat exchanger and from which the water heat-exchanged in the water-refrigerant heat exchanger is discharged, the water-refrigerant heat exchanger includes: a first inflow that guides introduction of the first refrigerant; and a first outflow from which the first refrigerant introduced through the first inflow and heat-exchanged is discharged; a second inflow that guides introduction of the second refrigerant compressed in the second compressor; and a second outflow from which the second refrigerant introduced through the second inflow and heat-exchanged is discharged, a first inflow that guides introduction of the first refrigerant; and a first outflow from which the first refrigerant introduced through the first inflow and heat-exchanged is discharged; a second inflow that guides introduction of the second refrigerant compressed in the second compressor; and a second outflow from which the second refrigerant introduced through the second inflow and heat-exchanged is discharged, the heat pump hot-water supply device further includes a guide tube that allows the second refrigerant discharged from the second outflow to be re-introduced into the water-refrigerant heat exchanger, the second expansion device being provided on the guide tube; characterized in that the heat pump hot water supply device further includes a bypass tube divided from the guide tube to extend to the outdoor heat exchanger; and a bypass valve provided in the bypass tube.