Abstract: An apparatus for forming a high purity silicon carbide film on the inner surface of a cylindrical member by a chemical vapor phase deposition process is provided. The member to be coated is received in a reaction vessel and heated by a heating means. The apparatus includes a gas feed conduit having a distal end disposed for axial motion within the member, for feeding a source gas containing a carbon source and a silicon source into the interior of the member, and a gas discharge conduit having a distal end disposed for axial motion within the member, for discharging used reaction gases from within the member. The gas feed and discharge conduits are moved so that their distal ends move through the member in unison to continuously move the reaction region.