The present invention is intended to enable efficient assembly of a fuel cell stack without causing any damage to the conductive separator. In a fuel cell including an anode, a cathode, an electrolyte membrane interposed between the anode and the cathode, and conductive separators each having manifold apertures 12 and a flow channel 16 for supplying a gas to the anode or the cathode, manifold aperture connecting portions 15 are formed at an inlet-side end and an outlet-side end of the flow channel 16, respectively. Each of the manifold aperture connecting portions 15 is recessed below the upper surface of the conductive separator 11. Cover plates are fitted and fixed to the recessed portions, respectively.