A battery includes a battery enclosure (3), a power-generating unit (50) accommodated in the battery enclosure (3), positive and negative terminal electrodes (1, 2). The battery enclosure (3) is composed of a laminate film compounded of metal and a polymer material, and has a rectangular shape. The power-generating unit (50) includes positive electrode collectors (5), negative electrode collectors (7) and separators (8). The positive and negative terminal electrodes (1, 2) have dimensions substantially equal to those of the positive and negative electrode collectors (5, 7), respectively. Further, the positive and negative terminal electrodes (1, 2) protrude from mutually different sides of the battery enclosure (3). The positive terminal electrode (1) is formed by protruding the positive electrode collectors (5) from the battery enclosure (3) in a state where end portions of the positive electrode collectors (5) are mutually stacked. The negative terminal electrode (2) is formed by protruding the negative electrode collectors (7) from the battery enclosure (3) in a state where end portions of the negative electrode collectors (7) are mutually stacked.