A substrate treatment method for treating a substrate, includes: (a) applying a coating solution to a front surface of the substrate by a spin coating method to form a coating film; (b) supplying a solvent for the coating solution to a projection of the coating film formed at a front surface peripheral edge of the substrate at (a); and (c) rotating the substrate in a state where the supply of the solvent is stopped, to move a top of the projection to an outside in a radial direction of the substrate. (b) and (c) are repeatedly performed. The projection is a buildup of the coating solution protruding from the coating film.