FUEL CELL SEPARATOR

A separator for a fuel cell includes protrusions that extend in parallel and are spaced apart from each other. The protrusions are configured to contact a power generation portion. The separator includes a gas passage that extends between two adjacent ones of the protrusions along the protrusions. The gas passage is configured to allow reactant gas to flow through the gas passage. The gas passage includes at least one rib that protrudes toward the power generation portion and extends in an extending direction of the gas passage. A downstream end of the rib includes a gradually-changing portion that gradually becomes farther from the power generation portion toward a downstream side.