A substrate processing method of supplying a processing solution to a substrate through a supply nozzle connected with a supply path via a differential pressure flowmeter provided on the supply path for supplying the processing solution and performing a process on the substrate by the processing solution, the method comprising:
- measuring a pressure value in the supply path by a pressure measurement unit included in the differential pressure flowmeter when the processing solution is not supplied to the substrate;
- determining whether the pressure measurement unit is operated normally by comparing the pressure value measured in the measuring process with a predetermined pressure value;
- and
- supplying the processing solution to a substrate if it is determined that the pressure measurement unit is operated normally in the determining process.