SUBSTRATE PROCESSING SYSTEM

PROBLEM TO BE SOLVED: To provide a substrate processing system which can stably maintain pressure inside a chamber, even if supply flow rate of an inert gas varies, and can shorten the time required for filling the chamber with the inert gas at initial operation by increasing the supply flow rate of the inert gas.SOLUTION: A substrate processing system comprises: a substrate processing unit which performs predetermined processing on a substrate; a chamber which accommodates the substrate processing unit in a sealed state; a gas supply unit which supplies an inert gas into the chamber; and a gas discharge unit which discharges the gas inside the chamber. Supply flow rate of the inert gas of the gas supply unit and discharge flow rate of the gas discharge unit are adjusted such that pressure inside the chamber becomes a chamber set pressure which is higher than pressure outside the chamber.