A method for manufacturing a hollow fiber blood treatment device comprises a hollow fiber membrane bundle obtained by bundling a plurality of hollow fiber membranes and having an outer shape formed into a cylindrical shape or a cylindrical shape and a hollow fiber membrane bundle attached to the outer peripheral portion of the hollow fiber membrane bundle And a sheet member, wherein the sheet member is a hollow fiber membrane. This manufacturing method has a mounting step of mounting the sheet body on the outer peripheral portion of the hollow fiber membrane bundle. Then, when carrying out the mounting process, the sheet material is mounted in a state in which the sheet material is previously formed as a cylindrical member. In addition, this sheet material is telescopic and has an inner diameter smaller than the outer diameter of the hollow fiber membrane bundle when it is formed into a cylinder in a natural state in which no external force is applied.中空糸型血液処理装置の製造方法は、多数本の中空糸膜を束ねて、外形を円筒状または円柱状に形成してなる中空糸膜束と、中空糸膜束の外周部に装着されたシート体とを備える中空糸型血液処理装置を製造する方法である。この製造方法は、中空糸膜束の外周部にシート体を装着する装着工程を有している。そして、装着工程を行なう際、シート材を予め筒状をなす部材として構成した状態で、シート材の装着を行なう。また、このシート材は、伸縮自在なものであり、外力を付与しない自然状態で円筒とした場合の内径が、中空糸膜束の外径よりも小さいものである。
