An operation status value detection unit detects two or more operation status values indicating an operation status of an internal combustion engine. A filtering processing unit applies filtering processing to the detected operation status values, and an operation status value difference calculation unit calculates the difference between the filter-processed operation status value and the corresponding non-filter-processed operation status value so as to calculate two or more operation status value differences. An operation status value difference normalization unit normalizes the two or more operation status value differences, based on predetermined reference values for the two or more operation status values, so as to calculate two or more normalized operation status value differences; and a transient correction unit corrects a control amount for controlling output of the internal combustion engine, based thereon, when the engine is in a transient-operation mode.