A battery including a first electrode layer and a second electrode layer disposed on the first electrode layer and serving as a counter electrode for the first electrode layer. The first electrode layer includes a first current collector, a first active material layer, and a first solid electrolyte layer. The first active material layer faces the second electrode layer with the first solid electrolyte layer therebetween. The first electrode layer has a polygon shape including a plurality of corner portions, at least one of the corner portions of the first electrode layer includes a first rounded portion. The first active material layer has a polygon shape including a plurality of corner portions, and the corner portion of the first active material layer, adjacent to the corner portion including the first rounded portion, includes a rounded portion.