To interrupt high responsiveness control not required upon actuating a furnace, by adding a function capable of selecting by an operator whether or not output correction of a furnace temperature control loop is executable.

This furnace temperature/combustion controller calculates a furnace temperature control amount MV corresponding to the magnitude of a deviation ΔSV between a furnace temperature set value SV and a furnace temperature measured value PV, and compares the deviation ΔSV between the furnace temperature set value SV and the furnace temperature measured value PV with a first reference value A, and when the deviation exceeds the first reference value, adds a predetermined correction amount ΔMV to the furnace temperature control amount calculated value MV, based uopon which a fuel flow rate and an air flow rate are subject to double cross limit control whereby heating furnace temperature is coincident with the furnace temperature set value SV. A deviation absolute value SV-PV between the furnace temperature set value SV and the furnace temperature measured value PV is compared with a second reference value B, and when the deviation absolute value converges within the second reference value, or when predetermined time passes after correction of the furnace temperature control amount calculated value is started, and further when an interruption operation input 313 is existent, the correction operation for the furnace temperature control amount MV is interrupted.