Process for producing pitch-based carbon fibers

In a process for producing carbon fibers from a carbonaceous pitch, the improvement characterized in that a trailing end portion of infusibilized fiber or carbonized fiber to be first subjected to a carbonizing or graphitizing treatment and the leading end of infusibilized fiber or carbonized fiber to be next subjected to the same treatment are bonded together using a composition consisting essentially of (a) at least one member selected from the group consisting of phenolic resins and pitches and (b) graphite powder in an amount in the range of 10 to 90 parts by weight per 100 parts by weight of component (a);

• wherein said bonding is carried out prior to or subsequent to the infusibilization of said fibers, and the thus-bonded fibers are fed successively to a carbonizing apparatus or a graphitizing apparatus.