Patent ID: 7660095

Claim:
A surge protector comprising: an insulating member having a conductive film divided by a discharge gap interposed therebetween; a pair of main discharge electrode members containing Cr(chromium), and one or more of Fe(iron), Ni(nickel), Co(cobalt) and Cu(copper), opposite to each other contacting the conductive film; an insulating tube fitted to the pair of main discharge electrode members opposite to each other to seal both the insulating member and a sealing gas inside thereof; and oxide films having an average thickness in the range of 0.01 to 2.0 μm formed on main discharge surfaces of the pair of main discharge electrode members by performing an oxidation treatment, the oxide films having a Cr (chromium) concentration that is higher at an exterior surface than at an interior surface adjacent to the respective electrode member wherein the chromium concentration of oxide film is at least 10% at the external surface.