A fuel cell stack including a plurality of fuel cells each formed by stacking separators and an electrolyte membrane-electrode assembly. The electrolyte membrane-electrode assembly includes an electrolyte membrane provided with a pair of electrodes on the opposite sides thereof. A stacked body formed by stacking the fuel cells is provided with a pair of end plates at the opposite ends thereof in a stacking direction. The end plates are integrally fixed by fastening members with the distance between the end plates maintained. A load measurement mechanism including a plurality of load sensors integrally connected to a connector member is provided between one of the end plates and the stacked body. The one of the end plates is provided with a pressure mechanism. The pressure mechanism presses the load measurement mechanism toward the stacked body to thereby apply a tightening load to the stacked body via the load sensors.