Provided is a temperature controller for an industrial heating apparatus adjusting a soak time on the basis of the variation of the thermal energy. Accordingly, since a temperature equilibrium time point of the center is determined by reflecting a temperature tolerance in the chamber and a soak time is corrected and since the temperature equalization time point is set on the basis of a full load state in which the variation of the input thermal energy per time is the smallest, the temperature at the center falls within an allowable upper/lower limit range even if a partial load state is applied, whereby the temperature control apparatus and method for an industrial heater applicable regardless of the amount of heating targets may be provided.