NOVELTY - The hydrogen-production apparatus has a power-generating plant (1), a hydrogen-production plant (2), a mixed-gas heat exchanger (12), a modifier (10), and a recovery equipment (13). The power-generating plant generates water vapor, the hydrogen-production plant generates hydrogen gas, and the mixed-gas heat exchanger produces a mixed gas. The modifier produces hydrogen-containing production gas by carrying out steam reforming of the fuel in the mixed gas. The recovery equipment separates and recovers hydrogen gas in the production gas.    USE - For producing hydrogen (claimed) in fuel-cell electric-power-generation systems and hydrogen-burning power-generation plants.    ADVANTAGE - The hydrogen-production apparatus enables efficient utilization of heat of water vapor extracted from the power-generating plant, and safe hydrogen production.    DETAILED DESCRIPTION - The hydrogen-production apparatus has a power-generating plant (1), a hydrogen-production plant (2), a mixed-gas heat exchanger (12), a modifier (10), and a recovery equipment (13). The power-generating plant generates water vapor, and the hydrogen-production plant generates hydrogen gas using the heat of the steam-extraction water vapor from the power-generating plant. The hydrogen-production plant is a fuel feed system (11) which heat-exchanges with respect to fuel and water containing hydrogen with the steam-extraction water vapor, and heats them. The mixed-gas heat exchanger mixes fuel and water, heats with the steam-extraction water vapor, and produces a mixed gas. The modifier produces hydrogen-containing production gas by carrying out steam reforming of the fuel in the mixed gas using the heat of steam-extraction water vapor. The recovery equipment separates and recovers hydrogen gas in the production gas. The fuel feed system, the mixed-gas heat exchanger, and the modifier are connected in parallel on piping (14a,14b) which supplies the steam-extraction water vapor. An INDEPENDENT CLAIM is included for hydrogen-production method.    DESCRIPTION OF DRAWING(S) - The figure shows the structure of the hydrogen-production apparatus. (Drawing includes non-English language text)    Power-generating plant (1)    Hydrogen-production plant (2)    Modifier (10)    Fuel feed system (11)    Mixed-gas heat exchanger (12)    Recovery equipment (13)    Piping (14a,14b)