A multi-spark ignition system for an internal combustion engine includes ignition coils each of which is mounted on one of spark plugs of an engine, an energy storing circuit, switching elements that repeatedly discharge electric energy stored by the energy storing circuit into the primary coil of the ignition coils; and a control circuit that controls the energy storing circuit and the switching elements according to consolidated signals each of which includes an energy storing command signal for storing electric energy into the energy storing circuit and a joint energy discharging period command signal for discharging the electric energy by the one of the spark plugs.
