A carbon filament comprising carbon layers and having a carbon structure in which the carbon layers are arranged substantially in the form of growth rings as viewed in cross-section, said carbon structure having an I.sub.1580 /I.sub.1360 ratio in Raman scattering spectrum of 1 or more and being readily convertible upon heating to a graphite structure. The carbon filament is efficiently produced in high yield from a hydrocarbon or a derivative thereof by a process in which specific species of catalysts are employed, preferably in combination with a filament-forming auxiliary, in specific amount proportions. The carbon filament and graphite filament are useful as filling materials for plastics, rubbers, paints, adhesives, ceramics, carbons and metals. They are also useful as an electrode material, electromagnetic wave shield, etc.