A combing cylinder of a comber includes a base and comb segments. The base includes mounting slots. Each comb segment includes a needle array and is detachably secured to the base via the associated mounting slot. The sizes of the needle arrays vary from one comb segment to another. The combing cylinder includes a cover. When at least one of the comb segments is detached from the base, the cover is mounted on the base to cover the mounting slot corresponding to the detached comb segment.