There is provided an ignition coil alleviating an insulating load between output terminals and at inside of the ignition coil and stabilizing insulating performance by constituting two outputs from the ignition coil by the same output electrode. Specifically, the invention is characterized in arranging two ignition plugs at a single cylinder, providing a center tap terminal at a secondary coil, regularly winding the secondary coil until reaching the center tap terminal and inversely winding the secondary coil from a regular winding direction to an inverse winding direction after reaching the center tap.