PURPOSE: To radiate colored light with high luminous intensity of a light source continuously by sticking a material which shows flame reaction on the surface of a cathode.

CONSTITUTION: When trigger current is supplied to a primary coil L1 of a transformer for voltage increase by a trigger oscillating circuit T, high voltage is generated in a secondary coil L2 and an arc is generated between an anode P and a cathode A. At that time, Ar gas or Xe gas, which touches the anode P, becomes cations and collides against a material 3 which is on the anode P and shows a flame reaction, so that a part of the material 3 showing flame reaction is repelled and gasified. Receiving a collision impact of electrons and cations, the gasified material 3 which shows flame reaction emits flame reaction colored light. When the whole electricity which is charged in a capacitor C is consumed for the arc discharging, the arc discharge is finished and the gasified material returns to the cathode again.