When a fully-closable expansion valve is used, there is a possibility that the expansion valve is fully closed thereby to block a refrigerant circuit. In an air conditioner 1 of the present invention, an indoor heat exchanger 14 includes an auxiliary heat exchanger 20 and a main heat exchanger 21 disposed leeward from the auxiliary heat exchanger 20. In an operation in a predetermined dehumidification operation mode, a liquid refrigerant supplied to the auxiliary heat exchanger 20 all evaporates midway in the auxiliary heat exchanger 20, i.e., before reaching the outlet. Therefore, only an upstream partial area in the auxiliary heat exchanger 20 is an evaporation region, while an area downstream of the evaporation region in the auxiliary heat exchanger 20 is a superheat region. Further, an evaporation temperature sensor 30 which detects an evaporation temperature is disposed downstream of an expansion valve 13 in an outdoor unit 3.