NOVELTY - A fuel cell system comprises a fuel cell (10) with an electrolyte membrane (5), a fuel electrode (4), an air electrode (6), an air chamber (50), and combustion chamber (80). In fuel cell system a hydrogen generating mechanism (30) is performed by reacting air and hydrogen generating material (40) containing steam, a hydrogen separation mechanism (20) is performed which is provided between combustion chamber and hydrogen generating mechanism, a introductory mechanism (90) is preformed which introduces air containing steam from air chamber into hydrogen generating mechanism.    USE - Fuel cell system such as polymer electrolyte fuel cell, is used for electronic devices (claimed) such as mobile telephone, electronic notebook, portable game apparatus, hand-held terminal, personal digital assistant, mobile digital versatile disc player, video equipment, camera and mobile generator.    ADVANTAGE - The compact fuel cell system has light weight, improved power density and effectively utilizes generated hydrogen.    DETAILED DESCRIPTION - A fuel cell system comprises a fuel cell with an electrolyte membrane, a fuel electrode formed on one surface of electrolyte membrane, an air electrode formed on another surface of electrolyte membrane, an air chamber which accumulates air containing steam generated using air electrode by power generation reaction of fuel cell, and a combustion chamber for holding fuel. In fuel cell system a hydrogen generating mechanism is performed by reacting air and hydrogen generating material containing steam, a hydrogen separation mechanism is performed which is provided between combustion chamber and hydrogen generating mechanism, separates hydrogen from hydrogen generating mechanism and supplies to combustion chamber, a introductory mechanism is preformed which introduces air containing steam from air chamber into hydrogen generating mechanism.    DESCRIPTION OF DRAWING(S) - The drawing shows perspective view of duel cell system.    Fuel electrode (4)    Electrolyte membrane (5)    Air electrode (6)    Fuel cell (10)    Hydrogen separation mechanism (20)    Hydrogen production mechanism (30)    Hydrogen generating material (40)    Air chamber (50)    Valve (60)    Air supply fan (70)    Combustion chamber (80)    Introductory mechanism (90)