PURPOSE: To quickly set furnace temp. to the target furnace temp. value by using normative model for regulating response relation between the target furnace temp. set value and the actual furnace temp. value and controlling control parameter for furnace temp. control unit so that the actual value coincides with the set value.

CONSTITUTION: At the time of heating while shifting a steel slab in a continuous type heating furnace 2, at first the target furnace temp. set value (r) is inputted to the furnace temp. control unit 4 having the valuable control parameter. The furnace temp. set value yM is obtd. with the normative model 6 for regulating the response relation between the target furnace temp. set value (r) and the actual furnace temp. value (y). Successively, output error (l) between the furnace temp. set value yM and the actual furnace temp. value (y) in the heating furnace 2 is calculated with an output error computing element 7, and the variable control parameter is controlled with an adaptation mechanism 8 attached to the furnace temp. control unit 4 so that the output error (l) asymptotically becomes zero. By this method, even if furnace dynamic characteristic varies caused by effect of load variation, etc., the furnace temp. is quickly set to the target furnace temp. value and unit consumption of fuel is reduced.