To provide an air conditioner capable of responding to smaller air conditioning load and load fluctuation as well as allowing enlargement of capacity by a plurality of compressors.

The air conditioner 10 includes an outdoor-side unit 11 having a plurality of capacity-variable type compressors A, B, C connected in parallel, an indoor-side unit 12 connected to the outdoor-side unit 11 via a refrigerant pipe 13, and a control part 21 for operating/controlling the compressors A, B, C. The plurality of compressors A, B, C have capacities different from one another. The control part 21 serially starts the compressors A, B, C from the one with smaller capacity according to the air-conditioning load of the indoor-side unit 12.