A substrate processing method for forming a resist film on a wafer with a base film being formed, and performing an exposure processing and a developing processing for the resist film to thereby form a desired resist pattern, has a base reflected light analyzing step of radiating a light of the same wavelength as an exposure light radiated during the exposure processing to the base film and analyzing a reflected light, before forming the resist film, and a processing condition control step of controlling at least one of a resist film forming condition and an exposure processing condition, based on the analysis of the reflected light. The method makes it possible to control a line width of a resist pattern with high precision.