PURPOSE: To provide the model predictive controller for executing optimal control to a control object without being put into disorder by a disturbance, a noise, etc.

CONSTITUTION: On the basis of the present manipulated variable and controlled variable, a state vector of a control object is estimated by a state observing device 4, and from this state vector, a controlled variable predictor is predicted in a predictive response calculating part 6. In an optimization calculating part 12, an optimal manipulated variable by which the controlled variable, the manipulated variable, and their variation rates satisfy a prescribed constraint condition, and also, a deviation of the controlled variable predictor and a future target value, and an evaluating function related to the manipulated variable are minimized, is derived.