A fuel cell stack formed by stacking a plurality of fuel cells in a stacking direction, the fuel cells each being formed by sandwiching an electrolyte electrode assembly between a first separator and a second separator, the electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between the anode and the cathode, wherein at least the first separator includes: a sandwiching section for sandwiching the electrolyte electrode assembly, a reactant gas channel for supplying a reactant gas along an electrode surface being formed in the sandwiching section; a reactant gas supply section, a reactant gas supply passage for supplying the reactant gas to the reactant gas channel extending through the reactant gas supply section in the stacking direction; and wherein a load absorbing mechanism is provided on the reactant gas supply section for absorbing a load applied in the stacking direction, and wherein the load absorbing mechanism includes: coupling members (100a, 100b) for coupling a pair of the reactant gas supply sections that are adjacent to each other in the stacking direction and allowing for reactant gas flow through each of the coupling members; and a seal member for preventing leakage of the reactant gas from the reactant gas supply section, characterized in that the coupling members (100a, 100b) between adjacent reactant gas supply sections are provided as a pair and have spring property for absorbing the load applied in the stacking direction by flexible deformation of said coupling members. a sandwiching section for sandwiching the electrolyte electrode assembly, a reactant gas channel for supplying a reactant gas along an electrode surface being formed in the sandwiching section; a reactant gas supply section, a reactant gas supply passage for supplying the reactant gas to the reactant gas channel extending through the reactant gas supply section in the stacking direction; and wherein a load absorbing mechanism is provided on the reactant gas supply section for absorbing a load applied in the stacking direction, and wherein the load absorbing mechanism includes: coupling members (100a, 100b) for coupling a pair of the reactant gas supply sections that are adjacent to each other in the stacking direction and allowing for reactant gas flow through each of the coupling members; and a seal member for preventing leakage of the reactant gas from the reactant gas supply section, characterized in that the coupling members (100a, 100b) between adjacent reactant gas supply sections are provided as a pair and have spring property for absorbing the load applied in the stacking direction by flexible deformation of said coupling members. coupling members (100a, 100b) for coupling a pair of the reactant gas supply sections that are adjacent to each other in the stacking direction and allowing for reactant gas flow through each of the coupling members; and a seal member for preventing leakage of the reactant gas from the reactant gas supply section, characterized in that the coupling members (100a, 100b) between adjacent reactant gas supply sections are provided as a pair and have spring property for absorbing the load applied in the stacking direction by flexible deformation of said coupling members.