PURPOSE: To reduce the number of parts, to simplify the circuit and to reduce the cost, in a 2-cycle gasoline engine, by igniting three ignition plugs simultaneously by means of a single ignition coil for every cylinder.

CONSTITUTION: In a 2-cycle 6-cylinder gasoline engine having three ignition plugs in single cylinder, the ignition sequence is No.1-No.6-No.2-No.4-No.3-No.5, where th ignition phase is shifted by 180°CA between No.1 and No.4 cylinders. Ignition plugs 11, 12, 13 are provided for No.1 cylinder, where the ignition plugs 11, 12 are connected to an ignition coil 1 for No.1 cylinder while the ignition plug 13 is connected to an ignition coil 4 for No.4 cylinder. Consequently, the ignition plug 13 is discharged approximately simultaneously through a diode D43 with same discharge timing as that of the ignition plugs 11, 12. It is arranged similarly for ignition plugs 41, 42, 43 of No.4 cylinder and other combination of cylinders connected similarly, thereby three ignition plugs for every cylinder can be ignited simultaneously by means of a single ignition coil for every cylinder.