The invention relates to the building industry. Application field of the invention is brittle materials (mainly concrete) reinforcement with short fibers. The objective of the invention is to increase resistance of a composite fiber to pullout from the matrix, obtaining better anchoring of the fiber ends in a concrete. The goal is achieved by increasing the size of the ends of the fiber. The inventive composite fiber is manufacturing in a continuous process with a pultrusion technique and subsequent cutting of the hardening fiber in necessary lengths. This is done by heating the fiber matrix (which connects the micro-fibers) to softening statement, then by turning the guillotine-type cutter and compressing cutted fiber ends transversely, deforming them at the same time.