There are provided a thermal processing apparatus, a method for regulating a temperature of a thermal processing apparatus, and a program, by which a temperature can be easily regulated. A control part 50 of a thermal processing apparatus 1 controls the apparatus so as to deposit SiO2 films on semiconductor wafers W, and judges whether the SiO2 films satisfy an in-plane uniformity. When the in-plane uniformity is not judged to be satisfied, the control part 50 calculates a temperature of a preheating part 23 by which temperature the in-plane uniformity can be satisfied. The control part 50 controls the apparatus so as to deposit SiO2 films on semiconductor wafers W under process conditions in which the temperature of the preheating part 23 has been varied into the calculated temperature, and the temperature of the preheating parts 23 is regulated. When the in-plane uniformity is judged to be satisfied, the control part 50 regulates temperatures of heaters 11 to 15 by the same procedure so as to satisfy an inter-plane uniformity.