Liquid lines (5LA, 5LB) and gas lines (5GA, 5GB) are connected to a main liquid line (4L) and a main gas line (4G) respectively so that a master outdoor unit (2A) and a slave outdoor unit (2B) are arranged in parallel with each other. On the gas line (5GB) extending from the slave outdoor unit (2B), a gas stop valve (V2) which is fully closed when the slave outdoor unit (2B) is deactivated during heating operation is disposed. On the liquid line (5LB) extending from the slave outdoor unit (2B), a liquid stop valve (V1) which is fully closed when the slave outdoor unit (2B) is deactivated during cooling operation and heating operation is disposed. Thus, compression of a liquid refrigerant and lack of a circulation amount of refrigerant are prevented.