The present invention relates to an air conditioner. In an air conditioner according to an embodiment, a scroll compressor having a refrigerating capacity of 23 kW to 58 kW and an amount of circulating refrigerant of 880 cc is used, a refrigerant mixture containing 50% or more of R32 is used as a refrigerant circulating the air conditioner, and a flexible stainless steel pipe having 1% or less of delta ferrite matrix structure on the basis of the grain size area is comprised in a refrigerant pipe. Therefore, the strength and hardness of the refrigerant pipe is maintained to be equal to or higher than those of a copper pipe, and the processability can be well maintained.