An object of the present invention is to provide a hollow fiber membrane with enhanced phosphorus-removing performance without impairing antithrombogenicity in order to inhibit in vivo accumulation of phosphate ions in living body that might cause bone metabolism disorders. The present inventors have found that a hollow fiber membrane having a specific membrane structure and a specific membrane composition possesses a very useful range for inner surface charges of the membrane. More particularly, the inventors have discovered that the above object can be achieved in a limited range in which the zeta potential on the inner surface of a hollow fiber membrane measured under given certain conditions is greater than -3.0 mV but less than 0 mV. This finding has led to the completion of the present invention.本發明者等係以改善成為骨骼代謝異常原因的蓄積於生物體內的磷酸離子,提供於不損及抗血栓性下,提高除磷性能之中空線膜為課題,於特定之膜結構及膜組成之中空線膜中,發現於膜內表面之荷電存在於極為有效之範圍。更具體上,係發現於一定之測定條件下,中空線膜內表面之剪面電位局限於吡-3.0 mV大,未滿0 mV之範圍,可達成上述目的而完成本發明。
