NOVELTY - A hydrogen processing system comprises modifier (30) which produces reformed gas, electrode structure which positioned anode electrode (22) and cathode electrode (23) which have gas flow path on both sides of electrolytic membrane (21), operation-control unit which performs hydrogen purification operations, electric power supply unit (60)which supplies electric power which is needed for hydrogen purification operations, power failure detection unit which detects power failure of commercial power source, electrical storage unit, and stop control unit.    USE - A hydrogen processing system.    ADVANTAGE - The hydrogen processing system suppresses increase in volume and increase in cost.    DETAILED DESCRIPTION - A hydrogen processing system comprises modifier (30) which produces reformed gas which modifies raw fuel and contains hydrogen, electrode structure which positioned anode electrode (22) and cathode electrode (23) which have gas flow path on both sides of electrolytic membrane (21), operation-control unit which performs hydrogen purification operations which permeate electrolytic membrane and transfer hydrogen in reformed gas to cathode electrode side, electric power supply unit (60) connected with commercial power source and supplies electric power which is needed for hydrogen purification operations, power failure detection unit which detects power failure of commercial power source, electrical storage unit, and stop control unit which performs first stop process with respect to electrode structure during execution of hydrogen purification operations using output electric power of electrical storage unit when power failure of commercial power source is detected by power failure detection unit. The anode electrode pumps ion by supplying reformed gas when predetermined voltage between anode electrode and cathode electrode is applied. The capacity of electrical storage unit is set to capacity corresponding to electric power which added part for predetermined allowances to electric power which is needed for first stop process.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of hydrogen processing system. (Drawing includes non-English language text).    Electrolytic membrane (21)    Anode electrode (22)    Cathode electrode (23)    Modifier (30)    Electric power supply unit (60)