PURPOSE: To eliminate limitations to the layout and assembly of an ignition system device, by bundling a plurality of electrical cords for ignition plugs so that the leading ends of thus bundled cords are led out through a tunnel formed in an engine body, and are connected to the connection terminals of a distributing device.

CONSTITUTION: A plurality of electrical cords 38 which are connected to the top ends of ignition plugs P in combustion chambers 6, are bundled, and are collected together into one electrical cord bundle B with the use of a cover member, and a cord cover 39 for covering the cord bundle B is secured on a cylinder head 2 through the intermediary of a packing 41 by means of a plurality of bolts 40. A tunnel 42 is formed in the cord cover 39, and the cord bundle B and the top ends of plural ignition coils are covered in the tunnel 42. The cord bundle B traverses through the tunnel 42 in the cover 39, and is led out from a take-out port opened to the end of an engine body. The led-out ends of the electrical cords are connected to the connection terminals of a distributor D carried by the engine body E. Accordingly limitations to the layout of the ignition may be eliminated and as well, it is possible to facilitate the maintenance of the engine.