A solid oxide fuel cell has a stack structure in which sheet bodies and separators for separating air and fuel gas are stacked in alternating layers. Each of the sheet bodies includes an electrolyte layer, a fuel electrode layer formed on the upper surface of the electrolyte layer, and an air electrode layer formed on the lower surface of the electrolyte layer, wherein these layers are stacked and fired in such a manner that the electrolyte layer is sandwiched between the fuel electrode layer and the air electrode layer. The thickness of the electrolyte layer is 0.3 μm or more and 5 μm or less, and the electrolyte layer is composed of a single particle of YSZ in the thickness direction. Thus, the electrolyte layer is extremely thin, and further, the grain boundary in the thickness direction is small. Accordingly, the IR loss (electric resistance) of the electrolyte layer can remarkably be reduced.