Abstract: An automated clean stock room employs an external air supply system having a plurality of fan filter units for supplying filtered clean air into the stock room, and an internal air circulation system having fans cooperating with air ducts and a plurality of filter screens to circulate and repeatedly remove pollution particles from the air supplied into the stock room. The fans of the internal air circulation system increase the speed of air flowing into a plurality of storage shelves provided by storage racks in the stock room, so that pollution particles in the air may be more quickly removed to upgrade the air cleanness in the stock room.