A substrate processing method is used for a substrate processing system having a substrate processing device and a substrate transfer device. The substrate processing method includes a substrate transfer step of transferring a substrate and a substrate processing step of performing a predetermined process on the substrate. The substrate transfer step and the substrate processing step include a plurality of operations, and at least two operations among the plurality of the operations are performed simultaneously. Preferably, the substrate processing device includes an accommodating chamber, a mounting table placed in the accommodating chamber to be mounted thereon the substrate, and a heat transfer gas supply line for supplying a heat transfer gas to a space between the substrate mounted on the mounting table and the mounting table.