There are provided porous fibers having excellent removal performance with respect to a material to be purified; and a purification column into which an adsorbent material obtained by bundling the fibers is incorporated. The porous fibers satisfying the following conditions (a) and (b) and having a shape in which three or more projected parts are continuously present in the lengthwise direction on the periphery part of a solid-state fiber: (a) The modification degree Do/Di in a cross section is 1.2 to 6.6 when the diameter of the inscribed circle is denoted by Di and the diameter of the circumscribed circle is denoted by Do., and (b) The specific surface area of pores is 50 m2/g or more.