A substrate processing method includes a substrate holding step that a substrate is held by a substrate holding unit that holds the substrate horizontally, a sealing step of sealing an internal space of a chamber in a state where the substrate holding unit that holds the substrate is housed in the internal space of the chamber, a liquid film forming step of forming a liquid film of processing liquid, which processes an upper surface of the substrate, by supplying the processing liquid to the upper surface of the substrate which is held horizontally, a pressurizing step of pressurizing the internal space until a pressure of the internal space reaches a first pressure which is higher than an atmospheric pressure, by supplying a gas to the internal space, a heating step of heating the substrate such that a vapor layer of processing liquid is formed between the liquid film and the substrate in a state where the pressure of the internal space reaches the first pressure, and a liquid film excluding step of excluding the liquid film from the substrate by evaporating the processing liquid, by reducing the pressure of the internal space until the pressure of the internal space reaches a second pressure, which is lower than the first pressure, while keeping a state where the vapor layer of the processing liquid between the liquid film and the substrate is formed.