Provided is a substrate processing method that prevents generation of watermarks on a substrate and can be performed at a low cost. The method controls the ambient humidity around the substrate depending on the kind of the chemical liquid, when the substrate is processed with the chemical liquid. The control of the humidity is performed at least in a drying step that dries the substrate W. In one embodiment, the ambient humidity around the substrate is controlled when a fluid containing IPA as a drying fluid is supplied to the substrate W after processing the substrate W with the chemical liquid.