A fuel cell stack comprising: a stacked body including unit cells stacked; end plates (14a, 14b) sandwiching the stacked body in a stacking direction in which the unit cells are stacked; a tension plate fastening the end plates (14a, 14b); fixing mechanisms fixing the tension plate to the end plates (14a, 14b); wherein at least one of the fixing mechanisms includes: a recessed portion formed in an outer peripheral edge (14a1) of one of the end plates (14a, 14b); a bolt hole formed in the one of the end plates (14a, 14b), formed concentrically with the recessed portion, and having an inner diameter smaller than the recessed portion; a through hole formed in the tension plate; a sleeve formed into a cylindrical shape with a through hole, and fitted into the through hole of the tension plate and the recessed portion; and a bolt penetrating through the through hole of the sleeve and screwed into the bolt hole, the through hole of the tension plate includes a tapered inner peripheral surface whose inner diameter gradually decreases toward the one of the end plates (14a, 14b) in an axial direction of the bolt, the sleeve includes a tapered outer peripheral surface whose outer diameter gradually decreases toward the one of the end plates (14a, 14b) in the axial direction, and the tapered outer peripheral surface is in surface contact with the tapered inner peripheral surface. a stacked body including unit cells stacked; end plates (14a, 14b) sandwiching the stacked body in a stacking direction in which the unit cells are stacked; a tension plate fastening the end plates (14a, 14b); fixing mechanisms fixing the tension plate to the end plates (14a, 14b); wherein at least one of the fixing mechanisms includes: a recessed portion formed in an outer peripheral edge (14a1) of one of the end plates (14a, 14b); a bolt hole formed in the one of the end plates (14a, 14b), formed concentrically with the recessed portion, and having an inner diameter smaller than the recessed portion; a through hole formed in the tension plate; a sleeve formed into a cylindrical shape with a through hole, and fitted into the through hole of the tension plate and the recessed portion; and a bolt penetrating through the through hole of the sleeve and screwed into the bolt hole, a recessed portion formed in an outer peripheral edge (14a1) of one of the end plates (14a, 14b); a bolt hole formed in the one of the end plates (14a, 14b), formed concentrically with the recessed portion, and having an inner diameter smaller than the recessed portion; a through hole formed in the tension plate; a sleeve formed into a cylindrical shape with a through hole, and fitted into the through hole of the tension plate and the recessed portion; and a bolt penetrating through the through hole of the sleeve and screwed into the bolt hole, the through hole of the tension plate includes a tapered inner peripheral surface whose inner diameter gradually decreases toward the one of the end plates (14a, 14b) in an axial direction of the bolt, the sleeve includes a tapered outer peripheral surface whose outer diameter gradually decreases toward the one of the end plates (14a, 14b) in the axial direction, and the tapered outer peripheral surface is in surface contact with the tapered inner peripheral surface.