A fuel cell layer, comprising: a plurality of membrane electrode assemblies, disposed in a planar arrangement, each membrane electrode assembly including an electrolyte membrane, an anode catalyst layer provided on one face of the electrolyte membrane and a cathode catalyst layer provided on the other face of the electrolyte membrane in such a manner that at least part of which is disposed counter to the anode catalyst layer; and an interconnector which electrically connects the anode catalyst layer of one of said adjacent membrane electrode assemblies to the cathode catalyst layer of the other of said adjacent membrane electrode assemblies, wherein said interconnector is formed of at least one of a material that constitutes the anode catalyst layer and a material that constitutes the cathode catalyst layer, wherein the anode catalyst layer in one of adjacent membrane electrode assemblies and the cathode catalyst layer in the other of adjacent membrane electrode assemblies overlap partially with each other as viewed planarly, wherein said interconnector is provided in a region where the anode catalyst layer in the adjacent membrane electrode assemblies and the cathode catalyst layer in the other thereof overlap with each other, the fuel cell layer comprises a seal layer for blocking the transfer of fuel and oxidant from one catalyst layer to the other catalyst layer by way of said interconnector, wherein said seal layer is provided in such a manner as to cover a face of at least one of the anode catalyst layer and the cathode catalyst layer in a region where the face of the at least one of the anode catalyst layer and the cathode catalyst layer overlaps with said interconnector as viewed planarly, wherein said plurality of membrane electrode assemblies are disposed in a planar arrangement such that the respective anode catalyst layers in each membrane electrode assembly are spaced apart from each other on the one face of the electrolyte member and the respective cathode catalyst layers in each membrane electrode assembly are spaced apart from each other on the other face thereof, characterized in that the electrolyte membrane has a through-hole running from the one face thereof to the other face thereof, wherein said interconnector is provided in the through-hole, and wherein said seal layer is provided in such a manner that at least one of fine pores of a material that constitutes said interconnector, fine pores of the anode catalyst layer adjacent to one end of said interconnector and fine pores of the cathode catalyst layer adjacent to the other end of said interconnector is filled by said seal layer. a plurality of membrane electrode assemblies, disposed in a planar arrangement, each membrane electrode assembly including an electrolyte membrane, an anode catalyst layer provided on one face of the electrolyte membrane and a cathode catalyst layer provided on the other face of the electrolyte membrane in such a manner that at least part of which is disposed counter to the anode catalyst layer; and an interconnector which electrically connects the anode catalyst layer of one of said adjacent membrane electrode assemblies to the cathode catalyst layer of the other of said adjacent membrane electrode assemblies, wherein said interconnector is formed of at least one of a material that constitutes the anode catalyst layer and a material that constitutes the cathode catalyst layer, wherein the anode catalyst layer in one of adjacent membrane electrode assemblies and the cathode catalyst layer in the other of adjacent membrane electrode assemblies overlap partially with each other as viewed planarly, wherein said interconnector is provided in a region where the anode catalyst layer in the adjacent membrane electrode assemblies and the cathode catalyst layer in the other thereof overlap with each other, the fuel cell layer comprises a seal layer for blocking the transfer of fuel and oxidant from one catalyst layer to the other catalyst layer by way of said interconnector, wherein said seal layer is provided in such a manner as to cover a face of at least one of the anode catalyst layer and the cathode catalyst layer in a region where the face of the at least one of the anode catalyst layer and the cathode catalyst layer overlaps with said interconnector as viewed planarly, wherein said plurality of membrane electrode assemblies are disposed in a planar arrangement such that the respective anode catalyst layers in each membrane electrode assembly are spaced apart from each other on the one face of the electrolyte member and the respective cathode catalyst layers in each membrane electrode assembly are spaced apart from each other on the other face thereof, characterized in that the electrolyte membrane has a through-hole running from the one face thereof to the other face thereof, wherein said interconnector is provided in the through-hole, and wherein said seal layer is provided in such a manner that at least one of fine pores of a material that constitutes said interconnector, fine pores of the anode catalyst layer adjacent to one end of said interconnector and fine pores of the cathode catalyst layer adjacent to the other end of said interconnector is filled by said seal layer.