According to the present invention there is provided an ignition system having a direct current source, a primary voltage stabilizing power source for the generation of a stabilized voltage from the direct current source, a high-tension transformer which receives the voltage from the primary voltage stabilizing power source and applies a high voltage developed on its secondary side to a discharge load, and a switching element for controlling the primary current in the transformer. At least two of those components are integrally connected, or means for detecting an abnormal condition of the direct current source is disposed within the case containing the primary voltage stabilizing power source, whereby connection or insulation between components can be done easily and there are attained simplification of the assembling work, reduction of noise and improvement of maintainability.