To reduce weight of the whole of an arrester and assembling manhours, in an arrester which dispenses with an upper and a lower bursting devices and bursts gas from the side surface.

A circular arc insulating bar 3 is fixed on a lower electrode 2, ZnO elements 4 are stacked in the insulating bar 3, and an electrode 1 is mounted above the ZnO elements 4. The electrode 1 is fixed to the tip part of the circular arc type insulating bar 3 with a screw 13 or the like. The part except the outer end surfaces of the upper and the lower electrodes 1, 2 are covered with a rubber jacket 14, and caps 8, 9 are mounted on both of the electrodes. Parts of ring trenches 1a, 2a arranged on the electrodes are compressively molded with a roll, from the outside of the caps, built in a unified body and hermetically sealed. Moisture caused by water vapor penetration through the rubber jacket is absorbed with desiccant 12.