Abstract: An anchoring structure is disclosed for connecting to a casing of an optical submarine repeater or a cable joint box an optical submarine cable which is composed of a cylindrical pressure proof layer formed by a combination of three deformed metal wires of the same sectorial cross-section and disposed inside an insulator so that the pressure proof layer has centrally thereof a circularly-sectioned optical fiber unit housing space for housing an optical fiber unit formed by at least one optical fiber, a cable tensile-strength member formed by a plurality of tensile-strength wires disposed concentrically with the cylindrical pressure proof layer on the outside thereof and a metallic tape layer disposed in a cylindrical form outside the tensile-strength member to extend in its axial direction, the seam of the metallic tape layer being welded and the insulator being disposed outside the metallic tape layer.