A cylinder identification apparatus for a multi-cylinder internal combustion engine. The apparatus includes the following units. A reference signal generator that senses the rotation of an engine crankshaft and generates a reference signal indicating each time the crankshaft is at a prescribed rotational angle. An identification signal generator senses the rotation of the engine camshaft or other member coupled to and rotating at 1/2 the speed of the crankshaft and generates a cylinder identification signal having a different form for different cylinders of the engine. A control unit identifies each cylinder of the engine based on the form of the cylinder identification signal.