A substrate coated with a coating solution is placed on a heating plate in a processing chamber in which an inert gas is circulating. The substrate is heated on the heating plate while the inert gas is circulating at an extremely small first circulating amount. The substrate is heated further on the heating plate while the inert gas is circulating at a second circulating amount larger than the first circulating amount. Detected is the density of the solvent in the processing chamber. The supply and exhaust amounts of the inert gas are controlled based on the density detected after the start of heating, so that an exhaust amount of the inert gas becomes a predetermined amount for a predetermined period until the solvent density reaches a predetermined density. A necessary control process is performed so that the solvent density reaches the predetermined density when the solvent density has not reached or exceeded the predetermined density after the predetermined period has elapsed. The two-time thermal-process or solvent-density control promotes evaporation of the resist solvent while restricting scattering of a photo-oxidizing agent included in the resist from being promoted beyond the wafer surface, thus achieving coated-film uniformity for the thermal process.