Fuel cell

An oxygen-containing gas flow field (32) for supplying an oxygen-containing gas from an oxygen-containing gas supply passage (20a) to an oxygen-containing gas discharge passage (20b) is formed on a first metal plate (14). The oxygen-containing gas flow field (32) includes oxygen-containing gas flow grooves (38a through 38c) as serpentine flow grooves having two turn regions T1, T2. The oxygen-containing gas flow grooves (38a through 38c) have substantially the same length. The oxygen-containing gas flow grooves (38a through 38c) are connected to an inlet buffer (34) and an outlet buffer (36) at opposite ends. The inlet buffer (34) and the outlet buffer (36) have a substantially triangular shape, and are substantially symmetrical with each other.