A heat pump according to the present invention comprises a plurality of the compression chambers, and compresses refrigerant with multistage, and injects vapor refrigerant into the space between the plurality of the compression chambers by using the first refrigerant injection flow path and the second refrigerant injection flow path. Performance and efficiency of the heat pump can be improved compared with non-injection, as flow rate of the refrigerant circulating the indoor heat exchanger is increased. Thus heating performance can be improved also in the extremely cold environmental condition such as the cold area by increasing the injection flow rate. Also, because the heat pump according to the present invention comprises the first refrigerant injection flow path and the second refrigerant injection flow path, refrigerant is injected twice. Thus, as the injection flow rate of the refrigerant is increased, heating capacity can be improved. Also, the difference between the suction pressure and the discharge pressure of the rotary compressor may be decreased, and thus the reliability and the performance of the rotary compressor can be improved.