A controller that processes a substrate by executing a process recipe for supplying at least a source gas to a process chamber to form a film on the substrate, and a pressure controller that controls the degree of opening of a pressure control valve on the basis of a pressure value detected by a pressure sensor that detects a pressure in a furnace during execution of the recipe and maintains the process chamber to a predetermined pressure. The pressure controller includes a memory that accumulates data acquired from the pressure sensor and pressure control valve, and measures a valve full close time to full close of the pressure control valve during execution of the process recipe and holds the valve full close time in the memory, and the controller acquires the stored valve full close time and confirms whether the acquired valve full close time falls within a threshold range.