Continuous fluorination of carbon is carried out by employing an apparatus for contact reaction of solid powder and reactive gas which comprises a horizontal reactor having a trough provided with weirs (e.g. height: 1 to 6 mm., interval: 5 to 30 cm.) and a vibrating means for vibrating the trough, and in which carbon particles supplied continuously are transported on the trough in a form of thin layer by the vibration of the trough while continuing the reaction by contacting efficiently the carbon particles with a fluorine gas. The contact reaction is efficiently conducted without accumulating the reaction heat to produce the fluorinated carbon in high yields, and the process is useful for the mass production. The apparatus is also useful for various contact reaction of a solid powder and a reactive gas.