PURPOSE: To hold an optical fiber securely by constituting a jacket tube of metal or resin when the optical fiber is coated with ceramic powder, and charging the ceramic powdery substance between the jacket tube and optical fiber.

CONSTITUTION: A pellet 1 is made of a ceramic material and has an infinite number of pores. This is obtained by mixing and kneading a binder with extremely fine ceramic powdery substance by ≥20% and then drying and degreasing the mixture. Powder 4 is applied outside the optical fiber 3 previously and made of extremely fine abrasive particles. This coating prevents a damage due to the direct contacting of the optical fiber. Extremely fine powder 51 of ceramic is applied over a ribbon wire 5 and serves as a lubricant.