An object of the present invention is to provide a hollow fiber membrane that can exhibit stable performance corresponding to an increase in blood flow rate and filtration rate by optimizing the structure of the dense layer on the inner surface of the hollow fiber membrane. It is the purpose. A hollow fiber membrane having a dense layer at least on the inner surface side, and when the inner surface of the hollow fiber membrane is observed with an atomic force microscope, a plurality of the membranes are oriented in the length direction of the hollow fiber membrane. Groove-like recesses are observed, the aspect ratio, which is the ratio of the length and width of the recesses, is 3 or more and 30 or less, the yield strength in the dry state of the hollow fiber membrane is 30 g / filament or more, and the elongation at break is 20% / A hollow fiber membrane characterized by being a filament or less. [Selection figure] None【課題】本発明は、中空糸膜の内表面の緻密層の構造を最適化することで、血流量およびろ過量の増加に対応して安定した性能を発現できる中空糸膜を提供することを目的とするものである。【解決手段】少なくとも内表面側に緻密層を有する中空糸膜であって、前記中空糸膜の内表面を原子間力顕微鏡で観察したとき、前記中空糸膜の長さ方向に配向した複数の溝様凹部が観察され、前記凹部の長さと幅の比であるアスペクト比が３以上３０以下であり、前記中空糸膜の乾燥状態における降伏強度が３０ｇ／ｆｉｌａｍｅｎｔ以上、破断伸度が２０％／ｆｉｌａｍｅｎｔ以下であることを特徴とする中空糸膜。【選択図】なし
