A small-sized gas ignition device comprising a self-oscillation circuit, a piezo-electric transformer which steps up the output of the self-oscillation circuit, a capacitor which accumulates the output voltage of the piezo-electric transformer, and a discharging gap which is connected in parallel with the capacitor and is adapted to discharge the accumulated voltage for performing gas ignition. With this device gas ignition is obtained with certainty by single operation requiring only a light touch.