Milled carbon fibers are provided which have a fiber cut surface and a fiber axis intersecting with each other at cross angles, the smaller one thereof being at least 65.degree. on the average. The milled carbon fibers may have a specific surface area as measured by the BET method of 0.2 to 10 m.sup.2 /g. The milled carbon fibers may be obtained by a process comprising melt spinning of mesophase pitch, infusibilization, milling of the infusibilized pitch fibers as obtained or after a primary heat treatment at low temperatures in an inert gas and a high-temperature heat treatment in an inert gas. Even when the graphite layer plane has achieved high-level growth, the above milled carbon fibers have low reactivity with a metal of high temperature or the like during the molding or use thereof because the proportion of reactive exposed surface of the inner portion of the fiber is small, so that the use of the milled carbon fibers can improve the mechanical strength and high-temperature heat resistance of the composite material.