The first carrier placing unit 2b includes a substrate transfer robot 21, a common carrier placing part 22, a turning and pushing-out part 27, a cleaning carrier transfer part 28, and a substrate transport robot 29. The substrate transfer robot 21, the common carrier placing part 22, and the turning and pushing-out part 27 are the same as those in the second preferred embodiment. The cleaning carrier transfer part 28 places the cleaning carrier WC thereon, while the substrate transport robot 29, which is movable in the X direction as indicated by an arrow 29X, transports the substrates W from the turning and pushing-out part 27 to the cleaning carrier transfer part 28.