The substrate processing unit 3b includes a cleaning carrier transport robot 31a, a plurality of cleaning parts 32, and a drying part 33. The cleaning parts 32 and the drying part 33 are almost the same as those of the second preferred embodiment. Upon the receipt of the cleaning carrier WC holding the substrates W from the cleaning carrier transfer part 28, the cleaning carrier transport robot 31 transports the cleaning carrier WC in the X direction as indicated by an arrow 31Xa. In accordance with this, the cleaning parts 32 and the drying 33 also handle the substrates W together with the cleaning carrier WC, which is different from the second preferred embodiment.