A battery includes a first current collector, first electrode layer, and first counter electrode layer. The first counter electrode layer is a counter electrode of the first electrode layer. The first current collector includes first front and rear face regions, second front and rear face regions, and a first fold portion. The first rear face region is a region situated on the rear face of the first front face region. The second rear face region is a region situated on the rear face of the second front face region. The first fold portion is situated between the first and second front face regions. The first current collector is folded at the first fold portion, whereby the first and second rear face regions face each other. The first electrode layer is in contact with the second front face region, and the first counter electrode layer with the first front face region.