In the present study performance tests on heat pump cycle have been carried out for near-azeotropic refrigerant R410A, pure refrigerant R1234ze (E) and zeotropic binary refrigerant mixtures of R1234ze (E) and R32 at heating mode and cooling mode, using a compressor for R410A. It is confirmed that the COP value, the heating capacity and cooling capacity of pure R1234ze(E) are the lowest among the refrigerants tested in the present study due to its low vapor density and latent heat. It is also found that adding R32 into R1234ze(E) dramatically improves not only the COP value but also heating and cooling capacities; the COP values of R1234ze(E)/R32(20/80 mass%) are almost the same as those of R410A at the same heating load and cooling load. As a result, the present cycle performance tests prove that, mixtures of R1234ze(E) and R32 are strong candidates for replacing R410A in domestic heat pump systems.