The present disclosure relates to a clothing treatment apparatus comprising: a first cabinet forming the outer appearance; a first drum of a cylindrical shape having open front and rear surfaces; a second cabinet located under the first cabinet; a tub located in the second cabinet; a second drum located in the tub to be rotatable and accommodating clothing; a first air suction duct for sucking the air in the first drum; a second air suction duct for sucking the air in the tub; a connection duct connected to the first air suction duct and the second air suction duct and including a heat exchanger for exchanging heat with the sucked air; a first exhaust duct for discharging the air, which has exchanged heat via the heat exchanger, to the first drum; and a second exhaust duct for discharging the air, which has exchanged heat via the heat exchanger, to the tub.