A substrate rotates, and a liquid nozzle of a gas/liquid supply nozzle moves to a position above the center of the rotating substrate. In this state, a rinse liquid is discharged from the liquid nozzle onto the rotating substrate. The gas/liquid supply nozzle moves toward a position outside the substrate. A gas nozzle reaches the position above the center of the rotating substrate, so that the gas/liquid supply nozzle temporarily stops. With the gas/liquid supply nozzle stopping, an inert gas is discharged onto the center of the rotating substrate for a given period of time. After that, the gas/liquid supply nozzle again moves toward the position outside the substrate.