FUEL CELL

The fuel cell according to the present invention has an anode, a cathode and a solid electrolyte layer. The cathode contains a perovskite oxide as a main component. The perovskite oxide is expressed by the general formula ABO3 and including La and Sr at the A site. The solid electrolyte layer is disposed between the anode and the cathode. The cathode has a surface on opposite side to the solid electrolyte layer. A first ratio of a Sr concentration relative to an La concentration is less than or equal to 4 times a second ratio of the Sr concentration relative to the La concentration. The first ratio is detected by use of X-ray photoelectron spectroscopy on the surface of the cathode. The second ratio of a Sr concentration relative to a La concentration is detected by use of X-ray photoelectron spectroscopy on an exposed surface. The exposed surface is exposed by surface processing of the surface. The exposed surface is positioned within 5 nm of the surface in relation to a direction of thickness.