In a fuel-cell stack in which a plurality of cells are stacked, each of the cells includes a membrane electrode assembly which is composed of a polyelectrolyte membrane and a pair of electrodes sandwiching the polyelectrolyte membrane, and a pair of separators by which the membrane electrode assembly is sandwiched, where the electrodes each have a catalytic layer brought into contact with the polyelectrolyte membrane and a gas diffusion layer brought into contact with the separator, and where a material of the gas diffusion layers is formed from carbon fiber woven cloth. In this fuel-cell stack, the warp direction and weft direction of the carbon fiber woven cloth are so set as to be uniform in all the cells with respect to the primary direction of the gas flow passages of the separators.