Fuel battery

In the fuel cell, an electrode layer on each of two surfaces of an electrolyte membrane is divided into a plurality of electrode regions by a dividing groove; a unit cell is constituted by a stacked structure including the electrolyte membrane, one electrode region on one surface of the electrolyte membrane, and one electrode region on the other surface thereof; and a plurality of the unit cells are connected in series by the interconnector part formed in the electrolyte membrane. At least the electrode layer on the one surface includes a catalyst layer having catalytic activity and containing proton conductive resin; and a protection layer located between the catalyst layer and the electrolyte membrane, having electric conductivity and having a higher filling density of proton conductive resin than that of the catalyst layer. The interconnector part is covered with the protection layer on the one surface.