Air conditioner

An air conditioner having a refrigerant circuit that maintains a high cooling efficiency and a sufficient amount of oil returned to a compressor even if the flow rate of refrigerant is decreased due to a low cooling load is provided. The refrigerant circuit includes a condenser (31), an expansion valve (32), an evaporator (33) and a variable displacement compressor (CM). The expansion valve (32) is normal-charge type. A control valve (CV) adjusts the pressure (Pc) in a crank chamber (5) based on the value of a current from a controller (70) and on a pressure difference ( DELTA P(t)) between two pressure monitoring points (P1, P2), which are located in the refrigerant circuit. Accordingly, the compressor displacement and the flow rate of refrigerant in the circuit are controlled.