Fuel cell stack

A fuel cell stack comprising a stacked plurality of single cells, each of the single cells having a membrane electrode assembly with a peripheral frame and a pair of separators holding the peripheral frame and the membrane electrode assembly between them, wherein

• the peripheral frame and the separators of each of the single cells have distribution holes that continue to each other in a stacked state to form a manifold configured to distribute reaction gas,
• at least a part of an inner wall of the manifold is formed in a continuous flat shape that extends in a stacking direction of the single cells, and
• the peripheral frame of each of the single cells comprises a rib that is disposed in an inner wall of each of the distribution holes and that protrudes at least from one side of the peripheral frame,
• the rib of the peripheral frame of each of the single cells protrudes at least from one side of the peripheral frame to cover the inner wall of the distribution hole of the separator,
• the peripheral frame of each of the single cells further comprises a flattening face that includes a side wall of the rib, and
• the flattening face of the peripheral frame of each of the single cells continues to an adjacent flattening face such that at least a part of the inner wall of the manifold is formed in the continuous flat shape that extends in the stacking direction of the single cells.