Provided is a cascade heat pump. The cascade heat pump includes a first refrigerant cycle including a first compressor and a first indoor heat exchanger, a second refrigerant cycle including a second compressor and a second indoor heat exchanger, an outdoor heat exchanger in which a refrigerant compressed in the first compressor or the second compressor is condensed, a bypass tube allowing the refrigerant compressed in the second compressor to bypass the first compressor, thereby flowing into a discharge side of the first compressor, and a first flow rate regulating part disposed on a discharge side of the second compressor to introduce the refrigerant discharged from the second compressor into one of the first compressor and the bypass tube.