A hollow-fiber-type blood processing device and methods for its manufacture include a hollow fiber membrane bundle which is obtained by bundling a large number of hollow fiber membranes into a columnar shape. A sheet body is mounted on an outer peripheral portion of the hollow fiber membrane bundle. The sheet body is expandable as a result of being woven from a sheet material. An inner diameter of the sheet body in a natural state where no external force is applied to the sheet body is smaller than the outer diameter of the hollow fiber membrane bundle.
