A band-shaped laminate having a flexible elongated substrate, a negative collector, a solid electrolyte, a positive active material, and a positive collector in this order is wound in a plate shape with the flexible elongated substrate placed inside. The band-shaped laminate that is laminated in a particular order is wound with the substrate placed inside, whereby a short-circuit occurrence ratio can be decreased. Furthermore, the band-shaped laminate includes the solid electrolyte, and is wound in a plate shape, whereby the reduction in thickness and the increase in volumetric energy density can be achieved.