Abstract: A sodium-sulfur storage battery comprises an alpha alumina ring, a sodium conductive solid electrolyte tube and solder glass jointing said ring and said tube together; and is characterized in that the alpha alumina ring is provided at its open end with a groove for collecting the solder glass, a width of said groove is in a range from 0.2 mm to 5 mm and a depth of said groove is in a range from 0.2 mm to 10 mm. A surface of the solder glass is formed at a position inner than an end surface of the alpha alumina ring. Said groove may have a section of a rectangular shape. An inside surface of said groove may have a section of a round shape or an oblique section.