PURPOSE: To obtain the titled fiber having improved image transmission performances, by packing optical fibers or parent materials having a clad layer of specific quartz glass on a quartz glass core having a dopant into a skin pipe of quartz glass, drawing the optical fibers or parent materials with the skin pipe.

CONSTITUTION: A great number of optical fibers or parent materials having a clad layer of quartz glass having 0.5W1μm thickness and at least ≥1,800°C drawing temperature on a quartz glass core having a dopant are packed in an arranged state into a skin pipe of quartz glass having ≥1,800°C drawing temperature. The surface of the skin pipe is washed with fluorine, etc. while being treated with ultrasonic wave, and the optical fibers or parent materials are drawn together with the skin pipe at 1,800W2,200°C optionally in state wherein the interior of the skin pipe is deaerated. Consequently, the clad outside the core prevents extraordinary flow deformation even if the core becomes a state of easy flow deformation, a multiple fiber having improved flexibility and image transmission performances is obtained.