A separator for a fuel cell is manufactured by preparing a raw material powder, uniformly mixing the prepared raw material to be formed into a slurry, and charging the raw material powder derived from granulation into a metal mold for heat press forming. The raw material is obtained by adding to carbon powder a binder containing a mixture of phenolic resin and epoxy resin. Therefore the heat press forming step does not cause the binder to generate gas, thus allowing manufacturing of a separator exhibiting sufficient gas-impermeability.