PURPOSE:To prevent the peeling of the primary film layer of an optical fiber, effectively protect the optical fiber and a lubricant susceptive to heat from welding heat, and continuously manufacture a metal tube-clad optical fiber cable for a long period. CONSTITUTION:A guide tube 55 is elastically pressed to the inner wall on the opposite side to the welded face of a metal tube 1 at the welding position and its vicinity, and the space between the welded face of the metal tube 1 and the guide tube 55 is widely secured to reduce the effect of welding heat. A lubricating material is stuck to an optical fiber 2 before the guide tube 55 is inserted, the optical fiber 2 is brought into contact with the inner wall of the guide tube 55 via the lubricating material, and the peeling of the primary film layer of the optical fiber 2 is prevented.
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