To further improve efficiency an air conditioner for conditioning air by pressurizing a sealing medium to a supercritical range, sealing it in an indoor cycle, and circulating the carrying medium inside the indoor cycle.

The air conditioner is provided with an outdoor cycle 9 having a compressor 2 for compressing refrigerant, a four-way valve 3 for switching a flow passage of the refrigerant, which is discharged from the compressor 2, in response to operation mode, an intermediate heat exchanger 6, in which the refrigerant and the carrying medium pass through, an expansion valve 5 for reducing pressure of the refrigerant or expanding the refrigerant to form a low-pressure refrigerant, and an outdoor heat exchanger 4 for exchanging heat between the refrigerant passing through inside thereof and open air, and provided with an indoor cycle 13 having a carrying medium driving device 10 for circulating the carrying medium pressurized to the supercricital range, the intermediate heat exchanger 6 and at least one indoor heat exchanger 11 for exchanging heat between the carrying medium passing through inside thereof and air to be fed into the room. In the intermediate heat exchanger 6, heat is exchanged between the refrigerant circulating in the outdoor cycle 9 and the carrying medium circulating in the indoor cycle 13. A heating means 7 for raising temperature of the gas refrigerant to be sucked by the compressor 2 is provided upstream of the compressor 2.