An air conditioner includes a cabinet including a front opening provided at a front surface thereof and a rear opening provided at a rear surface thereof; a heat exchanger provided inside the cabinet; a plurality of fans provided inside the cabinet and configured to allow air to pass through the heat exchanger; and a processor configured to control the plurality of fans so that in a cooling operation mode and a dehumidification operation mode, the plurality of fans are rotated in one direction so that the air is sucked through the rear opening, passes through the heat exchanger, and then is discharged through the front opening, and in an automatic cleaning operation mode, the plurality of fans are rotated in an opposite direction so that the air is sucked through the front opening, passes through the heat exchanger, and then is discharged through the rear opening.