Provided is an engine knocking detection apparatus capable of reasonably implementing necessary measures for water and dust proofing and against breaking of a cable, and the like at low cost as well as precisely detecting and effectively suppressing or avoiding knocking while suppressing cost and weight increases as much as possible. The engine knocking detection apparatus is adapted to detect knocking in an engine that adopts a flywheel magneto ignition system with an ignition coil unit securely attached to a cylinder, the ignition coil unit including an iron core, a coil wound around the iron core, and a control circuit board attached to the coil, and has an accelerometer for knocking detection attached to the iron core of the ignition coil unit.