There is provided 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 substrate processing method includes 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.