A fuel cell includes an electrolyte electrode assembly and a pair of separators sandwiching the electrolyte electrode assembly. Each of the separators is a single plate, and includes a plurality of circular disks. First protrusions and second protrusions are provided on both surfaces of the circular disk. The first protrusions contact the anode of the electrolyte electrode assembly to form a fuel gas flow field, and the second protrusions contact the cathode of the electrolyte electrode assembly to form an oxygen-containing gas flow field. The shape of the first protrusion is different from the shape of the second protrusion. The first and second protrusions are coaxial with each other.