A modified hollow-fiber membrane which has improved surface hydrophilicity without increasing the amount of components released therefrom, is less apt to interact with living-body components, does not adsorb proteins, and is less apt to deteriorate in performance. The hollow-fiber membrane has a copolymer of 2-methacryloyloxyethylphosphorylcholine and other polymerizable vinyl monomer held on a surface of the membrane, the copolymer being present on the surface in a higher concentration than in other parts of the membrane. The modified hollow-fiber membrane is useful in medical applications such as hemodialysis and blood filtration and in the medical industry, food industry etc.