PURPOSE: To suppress electric resistance and thermal resistance small, and reduce layering cost.

CONSTITUTION: Material is composed of two integrated type inclined carbon plates 30, 30 having thin and sealing property dense carbon layers 41 on one sides of fixed thickness porous carbon layers 40. Ribs R for the gas paths 2a, 2b thereof are formed on the other sides of the respective porous carbon layers 40 of the two inclined carbon plates 30, 30. The respective dense carbon layer 41 sides of one pair of rib R-formed inclined carbon plates 30, 30 are superimposed so as to form a separator 2 with ribs R. Since there is only one touching face, it is possible to suppress electric resistance and the like small, and to reduce layering cost.