Provided is an air-conditioning apparatus able to reliably apply control such that the discharge temperature does not become too high with a refrigerant such as R32 whose compressor discharge temperature readily rises, and thus suppress degradation of the refrigerant and the refrigerating machine oil. An injection pipe 4c that injects a heat source side refrigerant into a compressor 10 is installed, connected a pipe between a backflow prevention device 20 and an opening and closing device 24 installed on a branching pipe 4d, and an aperture unit in the compressor 10.