Disclosed is a substrate processing apparatus including a chamber, a first measuring unit, an exhaust pipe, a regulation valve, an opening degree detection unit, a valve controller, and a clogging detection unit. The chamber accommodates therein a substrate to be processed by using a processing fluid. The first measuring unit measures an internal pressure of the chamber. An exhaust from the chamber flows through the exhaust pipe. The regulation valve regulates an exhaust volume of the exhaust pipe. The opening degree detection unit detects a valve opening degree of the regulation valve. The valve controller controls the valve opening degree of the regulation valve based on a measurement result of the first measuring unit to keep the internal pressure within a specified range. The clogging detection unit detects clogging of the exhaust pipe based on the valve opening degree detected by the opening degree detection unit.