To provide a manufacturing method for a high-density fiber bundle having a diameter that is equal to or longer than a case inner diameter before being reduced to be equal to or shorter than the case inner diameter, and a manufacturing method for a blood purification column capable of housing the fiber bundle having the reduced diameter inside the case without a gap and without damaging the fiber bundle.SOLUTION: A manufacturing method for a high-density fiber bundle, a method for manufacturing a high-density fiber bundle including fibers between which a gap is reduced, includes: a step of grasping one end of a fiber bundle obtained by bundling fibers, the number of which is a predetermined number, before reducing and keeping a diameter of at least a portion in the longer direction of the fiber bundle on a side of the one end to a predetermined diameter by applying external force using a mold material provided at the outer periphery of the fiber bundle； and a step of reducing the diameter of the fiber bundle over the approximately whole length to the predetermined diameter by relatively moving the mold material in the longer direction of the fiber bundle to a side of the other end of the fiber bundle while making the fiber bundle and the mold material relatively rotate around the fiber bundle's axis.SELECTED DRAWING: Figure 1F【課題】 本発明は、ケース内径以上の直径を有する糸束をケース内径以下に縮径した高密度糸束の製造方法、ならびに、その縮径した糸束を隙間無く、かつ傷つけること無く、ケース内に収容することが可能な血液浄化カラムの製造方法を提供する。【解決手段】 糸同士の隙間が低減された高密度糸束を製造する方法であって、 所定本数の糸を束ねてなる糸束の一端を把持し、前記糸束の一端側における長手方向の少なくとも一部分を、前記糸束の外周に備えられた型材により外力を加えて所定の径まで縮径させて維持する工程と、 前記糸束と前記型材とを前記糸束の軸を中心に相対的に回転させながら、前記型材を前記糸束の他端側に向けて前記糸束の長手方向に相対的に移動させることにより、前記糸束を略全長にわたり前記所定の外径に縮径する工程とを含む、高密度糸束の製造方法。【選択図】図１Ｆ
