PURPOSE: To lower the concn. of org. solvent at the outlet for a gas to be treated and to improve cleanliness by providing a regenerating gas passage so that the regenerating gas is passed through each regenerating region from the other end of a rotary adsorber to one end and then passed through the regenerating region adjacent to the upper side in the rotating direction.

CONSTITUTION: A part of the cleaned gas from a pipeline 20 is branched into a pipeline 21 and used as the cooling and regenerating gas. The gas is firstly passed through the cooling region 17 from the other end of a rotary adsorber 11 to one end to cool the rotary adsorber 11 and then supplied to the other end of a regenerating region 16 adjacent to the upper side in the rotating direction from a pipeline 22 through a heater 23 to desorb the harmful and malodorous component. The regenerating gas is conducted to the other end of a regenerating region 15 adjacent to the upper side in the rotating direction from a pipeline 24 through a blower 25 and a heater 27 and supplied to the regenerating region 15. The regenerating gas is discharged from a pipeline 28.