NOVELTY - A high-temperature-steam electrolysis system consists of a water supplier (1), a temperature-rising portion (2), a condenser (3), a power supply (5), and a steam electrolyzer (10) consisting of a proton electroconductive solid electrolyte (13), a porous hydrogen pole (14), and a porous oxygen electrode (15). The solid electrolyte is formed as a partition in a container to form oxygen electrode chamber (12) and hydrogen pole chamber (11). The steam electrolyzer electrolyzes high-temperature steam supplied to the oxygen electrode chamber.    USE - System is used for high-temperature-steam electrolysis (claimed).    ADVANTAGE - The high-temperature-steam electrolysis system eliminates the need for reducing partial pressure in separation of hydrogen, steam, and produced oxygen.    DETAILED DESCRIPTION - A high-temperature-steam electrolysis system consists of a water supplier (1), a temperature-rising portion (2), a condenser (3), a power supply (5), and a steam electrolyzer (10) consisting of a proton electroconductive solid electrolyte (13), a porous hydrogen pole (14), and a porous oxygen electrode (15). The temperature-rising portion heats water supplied from the water supplier to form high-temperature steam. The solid electrolyte which does not transmit gas is formed as a partition in a container to form an oxygen electrode chamber (12) and a hydrogen pole chamber (11). The porous hydrogen pole is formed in the surface of solid electrolyte adjacent to the hydrogen pole chamber, and the porous oxygen electrode is formed in the surface of solid electrolyte touching the oxygen electrode chamber. The steam electrolyzer electrolyzes the high-temperature steam supplied to the oxygen electrode chamber from the temperature-rising portion, and discharges hydrogen from hydrogen pole chamber and oxygen-enriched steam from oxygen electrode chamber. The power supply supplies electric power to the steam electrolyzer. The oxygen-enriched steam discharged from the oxygen electrode chamber is heat-exchanged with a coolant. The condenser discharges the oxygen-enriched steam as oxygen and condensed water.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the high-temperature-steam electrolysis system.    Water supplier (1)    Temperature-rising portion (2)    Condenser (3)    Power supply (5)    Steam electrolyzer (10)    Hydrogen pole chamber (11)    Oxygen electrode chamber (12)    Proton electroconductive solid electrolyte (13)    Hydrogen pole (14)    Oxygen electrode (15)