To provide an air conditioner which can efficiently perform both heat exchange and the cleaning of a heat exchange gas by directly bringing the heat exchange gas into contact with a heating medium.

The air conditioner is provided with a direct contact type heat exchanger 10 which makes heat exchange by directly bringing the heat exchange gas into contact with the heating medium 11 of a liquid, etc., a transporting device 14 which transports the heat exchange gas into the heat exchanger 10, and a temperature control means 25 which controls the heat exchange gas heat-exchanged in the heat exchanger 10. The heat exchange gas can be heated or cooled efficiently through the heat exchange caused by directly bringing the gas into contact with the medium and, at the same time, can be cleaned with the medium. In addition, the temperature of the heat-exchanged gas can be adjusted easily and efficiently.