NOVELTY - The hydrogen production apparatus has light source (30) that emits light for causing the photo-catalytic action of the photo-catalyst. A hydrogen generator generates hydrogen by decomposing water by unit of the photo-catalyst (20) that is irradiated with light. A liquid light source is used as light source. The photo-catalyst is irradiated with light from the liquid light source while bringing the liquid light source closer to or into contact with the photo-catalyst.    USE - Hydrogen production apparatus for electric power generation system (claimed), for motor vehicle.    ADVANTAGE - The hydrogen production apparatus can irradiate light to the surface of photo-catalyst having complicated structure in efficient manner. Since the light source can be made to adjoin or contact even the structure of photo-catalyst is complicated by using liquid light source, the shadow portion can be prevented with respect to light source arising, and the production efficiency of hydrogen can be improved in efficient manner.    DETAILED DESCRIPTION - The photogen is distributed to the liquid. The luminous material is distributed to the liquid. The hydrogen-producing tank is stored with liquid light source. The photo-catalyst is positioned at the inner wall of the hydrogen-producing tank. The hydrogen-producing tank is provided with the flow path which pours the liquid light source. The photo-catalyst is positioned at the inner wall of flow path. The liquid light source is mixed with the water. The photo-catalyst is positioned at inner wall of hydrogen-producing tank. The flow path is adjoined to photo-catalyst and provided to pour liquid light source in hydrogen-producing tank. The flow path is provided to pour water so that photo-catalyst is contacted. The element is provided to separate flow path for liquid light sources and flow path for water of hydrogen-producing tank. The photo-catalyst is carried by the to-be-adhered main portion in which the unevenness is formed. The hydrogen-producing tank is provided to store liquid light source. The photo-catalysts are provided as grains so as to mix with liquid light source with the water. The inflow port is provided to take liquid light source into inside from exterior. The outflow port is configured to flow internal liquid light source out. The hydrogen removal opening is configured to take out outside the hydrogen which generated inside. The adjustment tank is provided to adjust liquid light source to the state in which light emission is possible so as to flow into inflow port. The micro-organisms decomposition tank is connected with cultivation tank. The organic substance produced by biodegradation and gas is supplied to cultivation tank. The photogen is provided with light emission bacteria and luminous plankton. The light emission bacteria are provided with photo-bacterium phosphoreum and vibrio fischeri. The luminous plankton is provided with noctiluca scintillans or peridinium penardii. The luminous materials are made of zinc sulfide, strontium aluminate, or sulfide fluorescent substance. The chemiluminescent solution is provided with fluorescent substance. The light emission wavelength of liquid light source is 500 nm or less. INDEPENDENT CLAIMS are included for the following:    (1) an electric power generation system has hydrogen storage portion which stores hydrogen and fuel cell electric-power-generated using hydrogen of hydrogen storage portion. An inverter is provided to convert electricity which fuel cell generated. The drain pipe is connected to micro-organisms decomposition tank, from home. The liquid light source is made to adjoin or contact photo-catalyst. The light from liquid light source is irradiated to photo-catalyst; and    (2) a hydrogen production method involves providing liquid light source including the photogen distributed to the liquid. The luminous material is distributed to the liquid.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the hydrogen production apparatus. (Drawing includes non-English language text)    Hydrogen-producing tank (10)    Photo-catalyst (20)    Light source (30)    Flow path of liquid light source (50)    Flow path of water (60)