PURPOSE: To enable ignition control even at the time of start-up by one electromagnetic pickup coil by deciding on a signal at one end of the electromagnetic pickup coil as the ignition signal of a certain cylinder and a signal at the other end as the ignition signal of another cylinder, and forbidding the ignition of the other cylinder excluding these two cylinders at the time of start-up.

CONSTITUTION: In case of the ignition device of a two-cycle three-cylinder internal combustion engine for an outboard motor, an electromagnetic pickup coil 21 is provided in proximity to a rotor 20, made of a magnetic body, rotated synchronously with a crankshaft, and signals at both ends of the electromagnetic pickup coil 21 are sent out onto lines a1, a2 respectively through shaping circuits 22, 23. The signals at both ends are combined in a shaping circuit 24, and then inputted into a computing element 26. The ignition timing is operated from these signals and the output signal of a throttle opening sensor 25, and ignition signals are outputted onto lines a2, b2, c2. The output signals of the lines a1-c1 or a2-c2 are selected by an ignition signal switching logical circuit 27 and applied to thyristers 7-9 related to the ignition coil 10 of each cylinder, and only two cylinders can be driven at the time of start-up and the like.