Disclosed is a clothes dryer, which includes: a main body in which a drum is rotatably installed; a circulation passage which becomes a path of the air passing through the drum in the main body to dry the clothes; a heat exchanger composed of an evaporator, a compressor, an expansion valve and a condenser to cool and heat the air on the circulation passage; an inlet port provided on one lateral surface of the main body to inhale the outdoor air; and an outlet port provided on the bottom surface of the main body to discharge the outdoor air.