A fuel cell stack includes a plurality of unit cells stacked in a stacking direction substantially along a direction of gravity. Each of the plurality of unit cells includes a first metal separator, a second metal separator, and a membrane electrode assembly sandwiched between the first metal separator and the second metal. A reactant gas channel allows a reactant gas to flow along a surface of each of the first and second metal separators. A reactant gas inlet manifold and a reactant gas outlet manifold allow the reactant gas to flow the reactant gas inlet manifold and the reactant gas outlet manifold in the stacking direction. A bridge portion forms a connection channel to connect at least the reactant gas outlet manifold to the reactant gas channel. The bridge portion includes a guide portion to break a continuity of condensed water.