The present invention relates to a method for heat processing a substrate. After a coating film is formed on the substrate, the substrate is baked at a predetermined high temperature. The baking step is performed by first increasing the substrate temperature from a predetermined low temperature to a predetermined intermediate temperature that is lower than a predetermined reaction temperature at which the coating film reacts. Next, a second baking step maintains the substrate at the predetermined intermediate temperature for a predetermined period of time, and is followed by a third step of increasing the temperature of the substrate to the predetermined high temperature that is higher than the predetermined reaction temperature. This results in uniform temperature within the surface of the substrate when the temperature of the substrate reaches the reaction temperature. Consequently, a chemical reaction due to heat processing of the coating film within the surface of the substrate is performed uniformly.