A process for producing pitch-derived carbon fibers from pitch fibers produced by melt-spinning a carbonaceous pitch, which comprises adding a polyoxyethylene alkyl ether of the following formula [I]:
wherein R represents an aliphatic hydrocarbon having 8 to 12 carbon atoms and n represents an integer of 3 to 9,
as an emulsifier in an amount of 1 to 12 wt. %, based on an amino-modified silicone oil, to this oil having a molecular weight of 500 to 5,000 and an amine value of 2 to 15 to obtain an aqueous silicone emulsion and then applying the thus obtained emulsion to the pitch fibers when or before bundling the pitch fibers thereby adhering said oil to the pitch fibers in an amount of 0.01 to 0.8 wt. % based on the fibers.