To provide a fiber bundle fixing method by which a swelling, etc., is not generated in a fixing part and also fixing is easily and more firmly attained.

The fiber bundle 10 to be planted is folded in two so as to be put through the through-hole 14 of a substrate 12 and a fixed length is made to be projected from the through-hole 14. When the tip of a heater 18 is made to gradually approach a substrate 10 in a state where the heater 18 is positioned just above the hole 14, the bending part of the fiber bundle 10 is fused at first, and, after that, fusing is quickly executed towards a substrate side 12. Moreover, when the heater 18 is lowered so as to permit the tip of it to be inserted to the hole 14, a whole fiber bundle 10 part projected from the substrate 10 is fused and enter into the hole 14 so as to fill up the inside of the hole 14. The fiber bundle 10 in the tip of the heater 18 is fused but the tip is made to approach the substrate in such a degree that the substrate is not fused. When the fiber bundle 10 projected on the back surface of the substrate 12 is fused in a fixed range, the heater 18 is lifted-up. Thus, the fused fiber bundle 10 is solidified inside the hole 14 and, in result, the fiber bundle 10 is firmly fixed in the part of the hole 14.