An intake air control apparatus for an internal-combustion engine includes an intake air adjusting device. An operating mode determination device is configured to determine whether the internal-combustion engine is in a predetermined high rotation speed and high load operation mode in which cooling is required by increasing an amount of fuel. An intake air reduction controller is configured to, if the operating mode determination device determines that the internal-combustion engine is in the predetermined high rotation speed and high load operation mode, control the intake air adjusting device so that an intake air amount is reduced in accordance with a rotation speed of the internal-combustion engine and an ignition timing in order to restrict a fuel injection quantity to be injected from a fuel injection valve so that the fuel injection quantity does not exceed a maximum fueling rate of the fuel injection valve.