Abstract: A method and apparatus for preparation of a graphite fluoride such as (CF).sub.n or (C.sub.2 F).sub.n by heterogeneous contact reaction between a carbon material such as graphite or petroleum coke and fluorine gas at about 200.degree.-550.degree. C. The carbon material in the form of small pieces such as granules or powder particles is kept in a holder having a number of openings so as to form a carbon material layer in the holder, which is placed in a reactor so as to leave gas passages around the holder. With heating, fluorine gas is forcibly passed through the gas passages without agitating the carbon material in the holder. The openings of the holder are shaped and arranged such that the fluorine gas permeates through the carbon material layer in the holder. For example, the holder is an open-type box made of either a wire screen or a perforated metal plate, or a conveyor belt made of a wire screen.