An ignition controlling apparatus that can diagnose a state of spark discharge in an internal combustion engine, and perform appropriate actions based on the diagnostic results. In the internal combustion engine ignition controlling apparatus, a signal extracting device extracts an ion current that is generated together with combustion of a gas mixture inside a combustion chamber by spark discharge of an ignition apparatus based on an ignition signal of an ignition coil, includes a signal diagnosing device that sets a predetermined detection zone from a period in a single stroke of an internal combustion engine from a first spark discharge commencement until after a last spark discharge completion, and that determines an ignition state based on parameters included in the signal extracted in this detection zone, and controls the internal combustion engine in response to this ignition state.