A substrate processing system includes: a measuring unit provided detachably with respect to a placement portion of a placement stage; a measuring jig for measuring a processing liquid; a liquid processing unit including a supplier which supplies the processing liquid to the measuring jig; a transfer mechanism for transferring the measuring jig between the measuring unit and the liquid processing unit; and a controller. The controller executes: a process of transferring the measuring jig in the measuring unit from the measuring unit to the liquid processing unit; a process of ejecting the processing liquid from the supplier to the measuring jig; a third process of transferring the measuring jig from the liquid processing unit to the measuring unit; and a fourth process of calculating an ejection amount of the processing liquid based on a measurement value in the measuring unit.