<p>[Problem] To provide a spark gap arrester having an enclosed structure in which: arc extinguishing performance is enhanced by generating sufficient arc extinguishing gas during the generation of electrical discharge and causing an arc resulting from lightning surge current to move in a reliable manner within an arc extinguishing plate; and in which melting and evaporation of the arc extinguishing plate that are caused by lightning surge current are reduced so as to increase the use life of the spark gap arrester. [Solution] An insulating discharge cap comprising a composite body of an insulating resin that generates arc extinguishing gas when heated and a conductive resin that generates arc extinguishing gas in a similar manner when heated are arranged between a pair of discharge electrodes. The discharge electrodes are arranged so as to face one another with an interval therebetween inside a cylindrical metal case, and form a circular truncated cone or round pillar shape. A plurality of arc-extinguishing metal plates are arranged with a predetermined interval therebetween on the outer surface of the insulating discharge cap, said arc-extinguishing metal plates being formed from a conductive sintered alloy configured by mixing and sintering one or more metals having a high melting point with one or more metals having a low melting point.</p>
