An ignition apparatus for an internal combustion engine is provided. The ignition apparatus includes an ECU. The ECU calculates a target value E* of an energy input amount of energy inputted into a spark plug based on an in-cylinder flow velocity v, a cylinder pressure P, and an air-fuel ratio AFR. The ECU also calculates a command value I* of a secondary current based on the in-cylinder flow velocity and control an operation of a second circuit according to the target value E* and the command value I*. The calculation of the target value E* using the in-cylinder flow velocity v, the cylinder pressure P, and the air fuel ratio AFR enables the energy input amount to be controlled according to the operating state of the internal combustion engine. The calculation of the command value I* based on the in-cylinder flow velocity v enables the secondary current to be controlled so as to eliminate a risk of the blowout of sparks. The ignition apparatus is, thus, capable of variably changing the amount of energy inputted to the spark plug to improve the fuel consumption.