A control apparatus includes: a tentative target calculator that calculates a tentative target value for a first physical quantity, based on a control target value; a correction calculator that calculates a correction value; and a first target value calculator that calculates as a first target value by adding the correction value to the tentative target value. When a second sensor fails, the first target value calculator designates the tentative target value as the first target value without adding the correction value to the tentative target value. The control apparatus further includes a variation inhibitor that inhibits the designated first target value from greatly varying due to the failure in the second sensor.