A battery 100 includes a power generating element 110 containing a solid electrolyte, and a first member 120 in contact with a principal surface 110c of the power generating element 110. The principal surface110c includes a central portion 110a and an end portion 110b with a ring-like shape surrounding the central portion 110a in a plan view. The first member 120 includes a central region 120a overlapping with the central portion 110a of the principal surface 110c in a plan view, and an end region 120b overlapping with the end portion 110b of the principal surface 110c in a plan view. At least one of the central region 120a or the end region 120b is in contact with the principal surface 110c. A Young's modulus of the end region 120b is smaller than that of the central region 120a.