A sheet body 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 fuel electrode layer is a porous layer including a first layer on a side close to the electrolyte layer made of fine particles of Ni and YSZ, and a second layer on a side apart from the electrolyte layer made of fine particles of Ni, YSZ, and ZrSiO4. The zircon particles are uniformly distributed in the second layer in the plane direction and in the stacking direction.