An electronic control device is provided for an aviation engine. Each cylinder of the engine is equipped with main ignition plugs and back-up ignition plugs. Lane A including a first CPU and lane B including a second CPU are included in an ECU. The ignition control system is multiplexed by the two lanes A, B. The first and second CPU independently calculate ignition timing for each cylinder based on each sensor signal, and then exchange the results of these calculations with each other. At each cylinder, ignition timing is synchronized in such a manner that ignition timing of the main ignition plugs and ignition timing of the back-up ignition plugs match. The electronic control device so configured has a high level of redundancy with a small number of CPU's. Thus, electronic control device can be provided for the aviation engine with few limitations placed in relation to installation location.