FUEL CELL SYSTEM

A fuel cell system capable of improving the chemical durability of a membrane electrode assembly by compensating for the amount of an antioxidant lost within the electrolyte membrane or electrode of the fuel cell stack in such a manner that the antioxidant is provided from an antioxidant supply device, provided in a fuel processing system and/or an air processing system, to a fuel cell stack, in preparation for a case where the antioxidant within the electrolyte membrane or electrode is lost due to the dissolution or migration characteristic of the antioxidant.