A control device includes a load fuel quantity calculation unit, an allowable fuel quantity calculation unit, a flow rate low value selection unit, a basic drive quantity calculation unit, a fuel deviation calculation unit, and a correction unit. The load fuel quantity calculation unit determines a load fuel quantity based on a required output. The allowable fuel quantity calculation unit determines an allowable fuel quantity to protect a gas turbine. The flow rate low value selection unit selects a minimum fuel quantity from among the determined fuel quantities. The basic drive quantity calculation unit determines a basic drive quantity of an air intake quantity regulator. The fuel deviation calculation unit determines a fuel deviation between the allowable fuel quantity and the minimum fuel quantity. The correction value calculation unit determines a correction value corresponding to the fuel deviation which is then used to correct the basic drive quantity.