A substrate treatment method of treating a treatment object substrate includes before applying a resist solution for forming a resist film onto a base film formed on a substrate surface of the treatment object substrate, making a determination of which one of a first treatment and a second treatment to perform based on the treatment object substrate. In response to the determination determining to perform the first treatment, performing the first treatment of decreasing a polarity of the base film to bring it closer to a polarity of the resist solution. In response to the determination determining to perform the second treatment, performing a treatment of increasing the polarity of the base film to bring it closer to the polarity of the resist solution.