A heat pump comprising: - a main circuit in which a compressor that raises a sucked low pressure refrigerant to an intermediate pressure to discharge the refrigerant as a high pressure refrigerant after further raising from the intermediate pressure to a high pressure, a condenser, a first flow rate control means, and an evaporator are sequentially connected by a main pipe, and a refrigerant circulates, the evaporator being divided into a plurality of parallel heat exchangers (4A, 4B), the parallel heat exchangers (4A, 4B) being arranged in parallel at respective parts of a parallel circuit formed by branching off the main pipe at an arranged position of the evaporator; characterized by further comprising: - a first bypass pipe whose one end is connected to the main pipe, through which the high pressure refrigerant discharged from the compressor flows to the condenser, and whose other end is branched off into parts that are connected to the main pipe on respective inlet sides of the parallel heat exchangers (4A, 4B); and - a second bypass pipe whose one end is connected to an intermediate portion of the compressor in which the refrigerant is raised to the intermediate pressure, and whose other end is branched off into parts that are connected to the main pipe on respective outlet sides of the parallel heat exchangers (4A, 4B), - wherein during a defrosting operation that removes frost on the parallel heat exchangers (4A, 4B), a part of the high pressure refrigerant discharged from the compressor is supplied through the first bypass pipe to a parallel heat exchanger that is defrosted, and the refrigerant that has been condensed by the parallel heat exchanger to be in a liquid state or a two-phase gas-liquid state is then passed through the second bypass pipe and is merged at a point where the refrigerant in the compressor is raised to the intermediate pressure. - a main circuit in which a compressor that raises a sucked low pressure refrigerant to an intermediate pressure to discharge the refrigerant as a high pressure refrigerant after further raising from the intermediate pressure to a high pressure, a condenser, a first flow rate control means, and an evaporator are sequentially connected by a main pipe, and a refrigerant circulates, the evaporator being divided into a plurality of parallel heat exchangers (4A, 4B), the parallel heat exchangers (4A, 4B) being arranged in parallel at respective parts of a parallel circuit formed by branching off the main pipe at an arranged position of the evaporator; characterized by further comprising: - a first bypass pipe whose one end is connected to the main pipe, through which the high pressure refrigerant discharged from the compressor flows to the condenser, and whose other end is branched off into parts that are connected to the main pipe on respective inlet sides of the parallel heat exchangers (4A, 4B); and - a second bypass pipe whose one end is connected to an intermediate portion of the compressor in which the refrigerant is raised to the intermediate pressure, and whose other end is branched off into parts that are connected to the main pipe on respective outlet sides of the parallel heat exchangers (4A, 4B), - wherein during a defrosting operation that removes frost on the parallel heat exchangers (4A, 4B), a part of the high pressure refrigerant discharged from the compressor is supplied through the first bypass pipe to a parallel heat exchanger that is defrosted, and the refrigerant that has been condensed by the parallel heat exchanger to be in a liquid state or a two-phase gas-liquid state is then passed through the second bypass pipe and is merged at a point where the refrigerant in the compressor is raised to the intermediate pressure. - a first bypass pipe whose one end is connected to the main pipe, through which the high pressure refrigerant discharged from the compressor flows to the condenser, and whose other end is branched off into parts that are connected to the main pipe on respective inlet sides of the parallel heat exchangers (4A, 4B); and - a second bypass pipe whose one end is connected to an intermediate portion of the compressor in which the refrigerant is raised to the intermediate pressure, and whose other end is branched off into parts that are connected to the main pipe on respective outlet sides of the parallel heat exchangers (4A, 4B), - wherein during a defrosting operation that removes frost on the parallel heat exchangers (4A, 4B), a part of the high pressure refrigerant discharged from the compressor is supplied through the first bypass pipe to a parallel heat exchanger that is defrosted, and the refrigerant that has been condensed by the parallel heat exchanger to be in a liquid state or a two-phase gas-liquid state is then passed through the second bypass pipe and is merged at a point where the refrigerant in the compressor is raised to the intermediate pressure.