An air conditioner of the present embodiment includes a heat exchanger unit in which an installation position of a suction temperature sensor can be changed and the air conditioner is capable of determining whether the installation position of the suction temperature sensor is correct. During a cooling operation, a heat exchange temperature is lower than a suction temperature, and during a heating operation, the heat exchange temperature is higher than the suction temperature. However, if a suction temperature sensor is incorrectly disposed on a downstream side of a flow of air in an indoor heat exchanger, the suction temperature detected by the suction temperature sensor is a temperature of indoor air after exchanging heat with a refrigerant in the indoor heat exchanger, so that the heat exchange temperature and the suction temperature are close to each other regardless of the cooling operation or the heating operation.