In an engine ignition system that includes a rotor that rotates in synchronism with rotation of an engine, an iron core fixedly disposed opposite the outer periphery of the rotor, and a primary coil and a secondary coil that are wound concentrically around the iron core, to reduce the weight of the rotor while allowing the rotational balance of the rotor to be easily adjusted, simplify the arrangement of the rotor itself, and secure an effectively usable space in the region on the inside of the rotor in the radial direction. Permanent magnets are fitted to the iron core having a plurality of legs opposite the outer periphery of the rotor at positions that are spaced in the peripheral direction of the rotor, and an inductor is fixed to the outer periphery of the rotor. The inductor forms a magnetic path for the magnetic flux that is formed by the permanent magnets between pairs of legs. The legs in a pair are adjacent to each other in the peripheral direction of the rotor, and the winding of the primary coil and the secondary coil around the iron core allows a spark plug to be energized every time the inductor passes the pairs of legs.