Abstract: A lightning-conducting insulator is disclosed, which comprises an insulator body consisting of a shed portion, a plurality of rib portions provided inside the shed portion, and a cup-like cylindrical head portion at a central upper portion of the shed portion, and a metal cap put and fixed onto the head portion, and a metal pin inserted and fixed inside the head portion. A cylindrical fitting section with a through hole is provided in the shed portion. At least one current-limiting element having a non-linear voltage-current characteristic is inserted into the through hole of the cylindrical fitting section. The cylindrical fitting section is sealed with a glass- and ceramics-bonding metal solder such that the upper and lower end faces of the current-limiting element and the end faces of the cylindrical fitting section may be continuously sealed.