PURPOSE: Coal tar pitch, as a starting material, is modified and made into short fibers, then the length of the fibers is adjusted, the resultant fibers are preoxidized, and calcined to produce carbon fiber that is suitably used to reinforce artificial graphite for electrodes, in low costs.

CONSTITUTION: Coal tar pitch, as starting material, is treated to remove substances insoluble in solvents, them melted, pressurized and jetted from a nozzle or a high-pressures gas stream is made to act on melted tar drops which flow down through small holes on the feeding pipe by pressure or spontaneously to form fine fibers. The fine fibers are made to collide to baffle plates and the resultant fibrous pitch is conveyed with a air stream and preoxidized as they pass through the reaction tube. Then, they are made to pass through a heating tube to effect calcination.