A fuel cell includes electromotive portions, a first sheet, a second sheet, a replenishing portion and a fuel adjusting film. The electromotive portions cause fuel and oxygen to react chemically with each other to produce electrical energy. The first sheet is provided to supply the fuel to the electromotive portions. The second sheet is provided to supply the oxygen to the electromotive portions. The replenishing portion is provided at a predetermined portion of the first sheet to replenish the first sheet with the fuel. The fuel adjusting film is inserted in the first sheet to adjust the amounts of the fuel to be supplied from the first sheet to the electromotive portions.