A clean room has a cleaned air feeding apparatus 1 having a rotor 2 adsorbing gaseous chemical substances to an adsorbing part 16 and desorbing the adsorbed gaseous chemical substances at the regenerating part 17. Drive 4 drives the rotor 2 to the adsorbing part 16 and the regenerating part 17. The gaseous chemical substances contained in the air are adsorbed, for removal, to the adsorbing part 16, and cleaned air is fed into a clean room main body 32. Heated regenerated air is fed to the regenerating part 17 so as to desorb the adsorbed gaseous chemical substances from the air.