Abstract: A high-energy ignition system for an internal combustion engine in which both magnetic and electrical energy stored in an energy storage coil and in a capacitor are supplied to the primary winding of an ignition coil at a predetermined timing. When a first or second switching device is turned off, the capacitor is charged with the energy stored in advance in the energy storage coil, and upon subsequent turning on of the first switching device, energy is stored in the energy storage coil from a DC power supply. At substantially the same time as the turning off of the first switching device at an ignition timing, the second switching device is turned on to supply the primary winding with the energy stored in the energy storage coil and the capacitor. Alternatively, the capacitor is charged with the energy stored in advance in the energy storage coil through the primary winding of the ignition coil and a charging diode at the time of turning off of the second switching device.