Temperature controller and temperature control method of steel plate

In the temperature control device 1 of the steel sheet according to an embodiment of the present invention, the state variable-disturbance estimation section 15 estimates a value of the state variable and the temperature disturbance variables of the control model at the same time, the furnace temperature change amount calculating section 16, using the values ​​of the state variables and the temperature disturbance variables of the control model, as the sum of squares of the deviation between the target value and the actual value of the temperature of the steel sheet at the exit side of the furnace becomes a minimum, each under the constraints calculating a furnace temperature change amount of the heating zone, the furnace temperature controller 17, calculated furnace temperature change amount to control the fuel flow rate used in each heating zone so as to achieve.