A dry cleaner easily and rapidly eliminates particles and dirt adhered to interior surfaces of the wafer carrier. The dry cleaner has a housing with a table mounted thereon, and an assembly for cleaning the wafer carriers disposed on the table. The cleaning assembly sprays a cleaning gas simultaneously into the carrier box and the cover of the wafer carrier. Dirt and particles separated from the carrier box and the cover are collected, by vacuum pressure through openings in the table, into a dirt-collector disposed in the housing, and then discharged through an exhaust tube. A controller controls a quantity of cleaning gas supplied and a time of cleaning by the cleaning assembly.