A surge protector coated with an oxide layer having an excellent chemical stability at the high temperature range and excellent adherence with respect to main discharge electrodes. The surge protector includes a column-shaped ceramic member that has a conductive film divided by a discharge gap interposed therebetween; a pair of main discharge electrode members opposite to each other on both ends of the column-shaped ceramic member to come in contact with the conductive film; and a cylindrical ceramic tube which is fitted to the pair of main discharge electrode members opposite to each other to seal both the column-shaped ceramic member and sealing gas inside thereof. Oxide films are formed on main discharge surfaces of at least the protrusive supporting portions of the pair of main discharge electrode members opposite to each other, by performing an oxidation treatment, respectively.