A triple-pipeline type first outdoor unit 2 provided with a first compressor 20 and a first outdoor heat exchanger 21, a plurality of indoor units 4A to 4D are provided, a second outdoor unit 3 provided with a second compressor 30, a second outdoor heat exchanger 32, and a second expansion valve 33, the first outdoor unit 2 is provided with a first four-way valve 60 that makes a refrigerant discharge pipe 25 of the first compressor 20 and a high-pressure gas pipe 7 capable of communicating with each other and if all the indoor units 4A to 4D perform a cooling operation at the same time, the first four-way valve 60 shuts off the communication between the refrigerant discharge pipe 25 and the high-pressure gas pipe 7, while a third four-way valve 51 is switched so as to connect a gas pipe 35d to the high-pressure gas pipe 7.