A fuel cell will play a part of a module of power generator instead of an internal- combustion engine. It is required to improve the productivity and miniaturizing of the fuel cell. The separator in the fuel cell is an important part. The manufacturing process of carbon/resin separators usually is injection molding or compression forming. On the other hand, the authors have developed die sliding extrusion based on the friction extrusion  and side flow extrusion . The die sliding extrusion is a kind of valuable shape extrusion [3,4]. It is applied to manufacturing fuel cell separators which have linear channels on its upper and lower surfaces in the orthogonal direction.