An ignition apparatus for an internal combustion engine can prevent malfunctions due to noise induced by a high ignition voltage which is developed by an ignition coil upon ignition. Generation of a misfiring detection signal can also be prevented during fuel supply cut-off operations. To these ends, in one aspect, and ignition apparatus includes: a controller for controlling the ignition of a cylinder of the engine in synchronism with the rotation thereof; a detector connected to a spark plug and an ignition coil for detecting an ion current which is generated between the electrodes of the spark plug upon combustion of an air/fuel mixture in the cylinder; and mask a for masking the output signal of the detector in response to discharge of the spark plug. In another aspect, an ignition apparatus includes: a controller for controlling the ignition of and the fuel supply to a cylinder of the engine in synchronism with the rotation thereof; a detector for detecting misfiring in the cylinder; and mask a for masking the output signal of the detector when the fuel supply to the cylinder is cut off.