Solid oxide fuel cell

A solid oxide fuel cell in which the catalytic activity of a fuel electrode is high and in which no poisoning by carbon occurs even when internal reforming is performed under a condition of a low S/C ratio and further in which the time course degradation of the fuel electrode is less when internal reforming is performed. In a solid oxide fuel cell having an oxide ion conductive solid electrolyte, and a fuel electrode and an air electrode connected to both faces thereof, a cermet of a catalyst and of the second solid electrolyte whose oxide ion conductivity is more than or equal to 0.2 S/cm at 1000 DEG C is used as the fuel electrode. More specifically, it is desirable that the second solid electrolyte is scandia-stabilized zirconia (ScSZ) containing 9 to 12 mol% of scandia.