Abstract: Disclosed herein are a process for producing a carbon fiber mat, having excellent production and energy efficiencies, comprising successively melt-spinning a fiber-forming pitch by a centrifugal spinning machine having a horizontal axis of rotation (parallel to the plane on which the spinning machine is placed), forming a mat by the thus spun pitch fibers, bringing the mat into an infusibilized state in an air atmosphere containing NO.sub.2 and calcining the thus infusibilized mat in an inert atmosphere, and an apparatus for carrying out the above-mentioned process.

Abstract: The present invention relates to a method for preparing carbon fibers from a pitch by melt-spinning the pitch, infusibilizing the pitch fibers with a mixture of air and a gaseous oxidizing agent in an infusibilizing furnace divided into at least two chambers arranged in series under the condition of a velocity of the circulation gas in a specified range and then carbonizing the thus treated pitch fibers into carbon fibers.

Abstract: The present invention relates to a method for preparing carbon fibers from a pitch by treating the pitch fibers spun from a pitch with a gaseous mixture of air and a gaseous oxidizing agent in an infusibilizing furnace divided into at least two chambers arranged in series and then carbonizing the thus treated pitch fibers into carbon fibers.