PURPOSE: To reduce the cost of a separator by using a nonpermeable plate- shaped molding as a main body, and passing a number of carbon rods through the molding in a dotlike arrangement, and integrally molding them, when forming the separator to be interposed between a plurality of cells in a battery.

CONSTITUTION: A separator 10 comprises a nonpermeable plate-shaped molding 11 and a number of carbon rods 12 scattered as dots on the molding 11. A nonpermeable material which can be easily molded such as synthetic resin is used for the molding 11, and the rods 12 are formed by baking carbon powder and then subjecting the powder to nonpermeability treatment, or they are formed by a material which is itself nonpermebale such as glassy carbon. To integrally mold these components, a plurality of recessed portions 13a, 13b of fixed depth are provided in both of the upper and lower surfaces of the molding 11 and the rods 12 are passed through the respective recessed portions while both ends of each rod are projected. Thus the recessed portions 13a is made to function as an air passage and the recessed portion 14b as a passage for reaction gas such as hydrogen and both of the passages are communicated with respective inner manifolds 14a, 14b provided or the respective outer peripheries of the passages.