NOVELTY - A hydrogen-producing apparatus (23) has a photoelectric conversion portion (2) comprising a light-receiving surface and a back surface, a portion which generates gas (a) provided on the back surface, and a portion which generates gas (b) provided on the back surface. One of the portion which generates gas (a) and portion which generates gas (b), is hydrogen-producing portion which generates hydrogen from an electrolyte solution, and the other is oxygen generation portion which regenerates oxygen from electrolyte solution.    USE - Apparatus is used for producing hydrogen (claimed) in hydrogen station and large-scale hydrogen production factory.    ADVANTAGE - The apparatus efficiently produces hydrogen.    DETAILED DESCRIPTION - A hydrogen-producing apparatus has a photoelectric conversion portion comprising a light-receiving surface and a back surface, a portion which generates gas (a) provided on the back surface, and a portion which generates gas (b) provided on the back surface. One of the portion which generates gas (a) and portion which generates gas (b), is hydrogen-producing portion which generates hydrogen from an electrolyte solution, and the other portion is oxygen generation portion which generates oxygen from electrolyte solution. The portion which generates gas (a) is electrically connected with the back surface. The portion which generates gas (b) is electrically connected with the light-receiving surface through a conductive portion (c1). An INDEPENDENT CLAIM is included for production of hydrogen, which involves installing hydrogen-producing apparatus such that light-receiving surface inclines with respect to horizontal surface, introducing electrolyte solution to the hydrogen-producing apparatus from lower portion of the hydrogen-producing apparatus, generating hydrogen and oxygen from hydrogen-producing portion and oxygen generation portion respectively by supplying sunlight to the light-receiving surface, and discharging hydrogen and oxygen from the upper portion of the hydrogen-producing apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of hydrogen-producing apparatus.    Substrate (1)    Photoelectric conversion portion (2)    Conductive portion (10)    Partition (13)    Hydrogen-producing apparatus (23)