A substrate processing apparatus includes: a substrate holder configured to hold a substrate; a processing liquid supply part configured to supply a processing liquid to the substrate held by the substrate holder; a chemical liquid supply part configured to supply a chemical liquid as a component of the processing liquid to the processing liquid supply part; a pure water supply part configured to supply pure water as a component of the processing liquid to the processing liquid supply part; a low-dielectric constant solvent supply part configured to supply a low-dielectric constant solvent as a component of the processing liquid to the processing liquid supply part; and a controller configured to control a ratio of the chemical liquid, the pure water, and the low-dielectric constant solvent contained in the processing liquid by controlling the chemical liquid supply part, the pure water supply part, the low-dielectric constant solvent supply part.