PURPOSE: To provide a device and a method for preventing the runaway of the integration term of a proportional-plus integral-plus-derivative controller which can be used in a feedback system.

CONSTITUTION: An error signal is supplied to the controller 35 by the feedback system. The controller 35 generates a control variable output signal from the error signal. The controller 35 gives a through rate limit to the control variable output signal. When the controller 35 is to drive the control variable output signal for exceeding the through rate limit, the integration term related to the controller 35 is controlled to a value by which the control variable output signal is compulsorily brought to the through rate limit value. Thus, the runaway of the integration term related to the controller 35 is avoided.