An air conditioner , comprising a refrigerant circuit in which a compressor , an outdoor heat exchanger , an expansion valve , and an indoor heat exchanger are connected to one another; a control unit; and an evaporation temperature detecting means for detecting an evaporation temperature, wherein: in a predetermined dehumidification operation mode, the indoor heat exchanger is structured to include a part where a liquid refrigerant supplied to a liquid inlet flows toward an upper end of the indoor heat exchanger , the indoor heat exchanger includes: (i) an evaporation region where the liquid refrigerant evaporates; and (ii) a superheat region downstream of the evaporation region, and the compressor and the expansion valve are controlled by the control unit so that the evaporation temperature detected by the evaporation temperature detecting means falls within a predetermined temperature range; characterised in that the control unit is configured such that: when a load increases, the frequency of the compressor is increased and an opening degree of the expansion valve is increased, and thereby an extent of the evaporation region varies to increase within the part where the refrigerant flows from the liquid inlet of the indoor heat exchanger toward the upper end of the indoor heat exchanger ; and when the load decreases, the frequency of the compressor is decreased and the opening degree of the expansion valve is decreased, and thereby the extent of the evaporation region varies to decrease within the part where the refrigerant flows from the liquid inlet of the indoor heat exchanger toward the upper end of the indoor heat exchanger . a refrigerant circuit in which a compressor , an outdoor heat exchanger , an expansion valve , and an indoor heat exchanger are connected to one another; a control unit; and an evaporation temperature detecting means for detecting an evaporation temperature, wherein: in a predetermined dehumidification operation mode, the indoor heat exchanger is structured to include a part where a liquid refrigerant supplied to a liquid inlet flows toward an upper end of the indoor heat exchanger , the indoor heat exchanger includes: (i) an evaporation region where the liquid refrigerant evaporates; and (ii) a superheat region downstream of the evaporation region, and the compressor and the expansion valve are controlled by the control unit so that the evaporation temperature detected by the evaporation temperature detecting means falls within a predetermined temperature range; characterised in that the control unit is configured such that: when a load increases, the frequency of the compressor is increased and an opening degree of the expansion valve is increased, and thereby an extent of the evaporation region varies to increase within the part where the refrigerant flows from the liquid inlet of the indoor heat exchanger toward the upper end of the indoor heat exchanger ; and when the load decreases, the frequency of the compressor is decreased and the opening degree of the expansion valve is decreased, and thereby the extent of the evaporation region varies to decrease within the part where the refrigerant flows from the liquid inlet of the indoor heat exchanger toward the upper end of the indoor heat exchanger . when a load increases, the frequency of the compressor is increased and an opening degree of the expansion valve is increased, and thereby an extent of the evaporation region varies to increase within the part where the refrigerant flows from the liquid inlet of the indoor heat exchanger toward the upper end of the indoor heat exchanger ; and when the load decreases, the frequency of the compressor is decreased and the opening degree of the expansion valve is decreased, and thereby the extent of the evaporation region varies to decrease within the part where the refrigerant flows from the liquid inlet of the indoor heat exchanger toward the upper end of the indoor heat exchanger . <EOS>