Cylinder identification apparatus and cylinder identification method for engine

Cylinder judgment signals are output from a plurality of cam sensors at every uneven crank angle interval. The number of cylinder judgment signals output from one cam sensor during a time of period between a previous output and a present output of cylinder judgment signals from the other cam sensor, is counted up, to judge a specific cylinder based on the number of outputs, so that cylinders other than the specific cylinder are judged based on the judgment result and the cylinder judgment signals, and at the same time, each time the cylinder is judged by the above method, a period of from the previous cylinder judgment to the present cylinder judgment is calculated, to judge erroneous detection of cylinder judgment signal due to noise based on a ratio between a previous calculation value and a present calculation value of the period, and when the erroneous detection is judged, the cylinder judgment result based on the cylinder judgment signals is canceled.