A fuel cell includes a membrane-electrode assembly and a separator. The membrane-electrode assembly has an electrolyte and a pair of electrodes that are disposed on respective sides of the electrolyte. The membrane-electrode assembly and the separator are stacked in a stacking direction. A reaction surface of the membrane-electrode assembly is in a vertical direction along a direction of gravity and has a shape having a longer dimension in a horizontal direction. The fuel cell is provided with a reactant gas passage to allow a reactant gas to flow along a longitudinal direction of the reaction surface. The reactant gas is an oxidant gas or a fuel gas. A drain channel to allow product water from the reactant gas passage to be drained away is disposed between the membrane-electrode assembly and the separator and under the reaction surface in the direction of gravity.