Provided is a porous fiber that is a solid fiber having a modified cross-sectional shape and that satisfies the following (a) and (b): (a) when, in a transverse cross section of the solid fiber, the diameter of an inscribed circle is Di and the diameter of a circumscribed circle is Do, a modified cross section degree Do/Di is 1.20-8.50； and (b) the specific surface area of the fiber pore is not less than 30 m2/g. Also provided is an absorbing material that contains not less than 28 vol% of the porous fiber as a fiber bundle. Also provided is a purifying column formed from: the absorbing material being arranged in a case axial direction and in a straight shape； and a plastic casing having both ends at which an inlet port and an outlet port for a liquid to be treated are provided. The present invention thus provides: the porous fiber that allows efficient absorption of a substance to be removed in the liquid to be treated； and the purifying column having the porous fiber embedded.一種多孔質纖維，其為異形截面形狀之實心纖維，且滿足以下(a)~(b)：(a)於該實心纖維的橫截面中，將內切圓的直徑設為Di、外接圓的直徑設為Do時，異形度Do/Di為1.20~8.50；(b)纖維的細孔比表面積為30m2/g以上。一種吸附材料，其係包含28vol%以上之纖維束形態的上述多孔質纖維而成。一種淨化管柱，其中上述吸附材料係沿套管軸方向排列成筆直形狀，且於塑膠套管的兩端安裝有被處理液之入口埠、出口埠而成。提供一種可有效地吸附被處理液中之去除對象物質的多孔質纖維及內置有多孔質纖維的淨化管柱。
