To reduce the shock generated on the moment of shift 'IN' in an outboard engine, equipped with a shifting mechanism to connect the engine side with the propeller side using a dog clutch, without having to set the idling speed to low in normal operation.

If the shifting condition for going out of the neutral position is sensed, while the situation is such that the engine is idling and the shifting is in the neutral position, a control is made so that the engine revolving speed sinks, and if shifting 'IN' is sensed, at least the described control is disengaged.