According to the present invention, an excellent battery is provided. A battery according to an exemplary embodiment of the present invention includes a first electrode layer (6), a second electrode layer (7), and a charging element (3) to which a charging voltage between the first and second electrode layers is applied. The charging element (3) can form an energy level in a band gap by causing a photoexcited structural change of an n-type metal oxide semiconductor covered with an insulating substance and thereby capture an electron. For example, the battery has a configuration in which the charging element (3) is formed in a three-dimensional shape.