For utilizing the chemical energy of a sugar directly as electric energy, electrolytic oxidation of a sugar on the negative electrode associated with cleavage of a carbon-carbon bond thereof is employed, thereby generating an electromotive force between the positive electrode and the negative electrode having an electrolyte therebetween. For an efficient oxidation of a sugar, it is effective for the negative electrode to have a component capable of forming a coordination compound with a sugar via a hydroxyl group thereof. Such a component may comprise a metal element capable of forming an amphoteric hydroxide. Use of an oxygen electrode as the positive electrode gives a battery capable of efficiently converting the chemical energy of a sugar into electric energy.