A substrate processing apparatus includes a chamber configured to dispose a substrate to be processed with a substrate holder, a spin chuck to rotate the substrate, a gas discharging head configured to discharge a dehumidified gas to the substrate, a processing liquid supply nozzle, an IPA supply nozzle, and a driving device configured to move the gas discharging head between a retreat position of an upper part of the chamber and an approach position near the substrate. In particular, the gas discharging head is positioned at the approach position when the IPA is supplied to the substrate so that the dehumidified gas is supplied from the gas discharging head to the substrate when the IPA is supplied to the substrate.