A substrate processing method includes a liquid film forming step of forming a liquid film, a liquid film heat retaining step of keeping the liquid film warm, a gas phase layer forming step of forming a gas phase layer which holds the processing liquid on a center portion of the liquid film, an opening forming step of forming an opening in the center portion of the liquid film by excluding the processing liquid held by the gas phase layer, a substrate rotating step of rotating the substrate around a rotation axis, and an opening expanding step of expanding the opening, while a state in which the gas phase layer is formed on an inner circumferential edge of the liquid film is maintained, by moving the irradiation region toward a circumferential edge portion of the substrate while the liquid film heat retaining step and the substrate rotating step are performed.