CLEAN ROOM

PROBLEM TO BE SOLVED: To prevent the diffusion of gas component by removing the generated gas component having odor inside a clean room conducting it to a first gas removing filter by a blower on the back surface side of a floor and filtering the both of the air conducted to an under floor space and the air filtered by the gas removing filter by a second gas removing filter in an air flow duct. SOLUTION: Clean air is supplied to the inside of a room 21 from the inside of a ceiling space 23 through a fan filter unit 22, sent to an underground space through an air flow hole 25 and flown into the circulation path returning it to the ceiling space 23 through an air flow duct 30 adjusting the temperature of it to the predetermined temperature by a cooling coil 32 after removing the low density gas by a gas removing filter 31. The air is supplied to equipment 26 from a fan filter unit 22 being provided with the fan 22b of a region A that is arranged with the equipment 26 and the air is sucked by a fan 29 arranged on the lower surface side around the equipment 26. The gas component or component having odor leaked from the equipment 26 is conducted to a gas removing filter 28 and after removing it, the air is exhausted to an under floor space.