Further, the number of holding plates 211 of the substrate transfer robot 21 does not always have to be equal to the number of substrates W held in the common carrier SC or the exclusive carrier EC. For example, the following case may be possible: the common carrier SC can store 25 substrates W; the exclusive carrier EC can store So substrates W; and the substrate transfer robot 21 can hold 5 substrates W at a time. In this case, instead of the transfer methods of the aforementioned preferred embodiments, the substrate transfer robot 21 repeatedly transfers 5 substrates W until all the substrates W held in the two common carriers SC are transferred into one exclusive carrier EC.