Substrate processing method and substrate processing apparatus

A substrate processing method includes supplying a water-soluble polymer solution to a surface of a substrate having, on a surface of the substrate, a resist film on which no pattern is formed, after an immersion exposure process, hydrophilizing a surface of the resist film using the supplied water-soluble polymer solution, supplying, after the hydrophilizing, a cleaning liquid to the surface of the substrate while rotating the substrate to remove the water-soluble polymer solution that has not contributed to the hydrophilizing, and drying the substrate supplied with the cleaning liquid, wherein the water-soluble polymer solution has a pH value that allows an acid concentration in the resist film to fall within a permissible range.