PURPOSE: To manufacture a wave-guide optical fiber for the transmission of high-energy laser beam, having flexibility, by depositing a substance reflecting high-energy laser beam to the inner wall of a soda-lime glass hollow optical fiber by electroless plating.

CONSTITUTION: A large-sized core glass 2a made of acid-soluble glass is inserted in a large-sized cylindrical sheath glass 1a made of soda-lime glass, and the assembly in heated at about 700W900°C in a furnace 3 and drawn by the drawing roller 4 to obtain a fiber having an outer diameter of the sheath glass of about ≤1,500μm and a sheath thickness of about 100W300μm. The spun glass is suspended with the tool 7 and put into a vessel 6 containing nitric acid 5 of about 1N concentration and about 70°C to dissolve and remove the core glass 2b. an end of the obtained hollow sheath glass 1b is melted and sealed with the burner 8. An ammoniacal silver nitrate solution is filled in the sealed sheath glass 9 to deposit silver by the electroless silver plating process, and then, the sealed part is cut off to obtain a strong and harmless optical fiber for the transmission of high-energy laser beam.