To lower the temperature of an air for regenerating adsorbent and to sufficiently secure the humidifying quantity to be fed to a room inside in an air conditioner having the adsorbent releasing water content adsorbed in regeneration to the flowing air.

This air conditioner is provided with adsorption devices 81, 82,... formed with a humidity control side passage 85 having the adsorbent contacting with the flowing air, and a cooling side passage 86 allowing the air to pass for taking the adsorption heat of the humidity control side passage 85 respectively; and heating means 92 heating the air for regenerating the adsorption devices 81, 82,.... This air conditioner is so formed that the heating means 92 heats the air to be fed inside the humidity control side passage 85 of the adsorption devices 81, 82,... so that the regeneration temperature of the adsorption devices 81, 82,... reduces to 55°C or less.