An engine ignition system and the like are provided, which reduce a required voltage and improve an ignition performance without any special electrical configuration. An ignition system is configured so that: to an auxiliary electrode is applied a voltage that is not more than a voltage applied between a center electrode and a ground electrode and that generates no spark discharge; the auxiliary electrode is positioned so that an electric field Ef2 between the auxiliary electrode and the ground electrode or an electric field Ef3 between the auxiliary electrode and the center electrode, which is generated by the applied voltage, is spread over the gap. A time for applying the voltage to the auxiliary electrode is controlled to include a time for applying the voltage between the center electrode and the ground electrode.