To provide an air conditioner capable of improving the efficiency of a compressor by adjusting an amount of oil to be returned to the compressor.

In the air conditioner 10 having an oil return pipe 23 having an compressor 15 and an oil separator 17, and returning oil which is separated by the oil separator 17 to the compressor 15, a motor operated valve 23A is provided in an oil return pipe 23, and a valve opening control means 100 is provided for controlling an opening of the motor operated valve 23A according to the number of revolutions of the compressor 15.