A cell according to the present disclosure includes: a first electrode layer; a solid electrolyte layer on the first electrode layer, the solid electrolyte layer containing Zr; a middle layer on the solid electrolyte layer, the middle layer containing CeO2 which contains Ce and a rare earth element other than Ce; a second electrode layer on the middle layer; and a boundary region between the solid electrolyte layer and the middle layer, the boundary region including a basing point at which a molarity of Ce and a molarity of Zr are equal. An average molarity of the Ce within a range from the basing point up to 3 μm toward the solid electrolyte layer is equal to or less than 10 mol % with respect to a total of Ce, Zr, and other rare earth elements, an average molarity of Zr within the range is equal to or more than 70 mol % with respect to a total of Ce, Zr, and other rare earth elements, or a molarity ratio of Ce with respect to Zr within the range is equal to or less than 0.143.