NOVELTY - A hydrothermal decomposition apparatus (41) performs hydrothermal decomposition by contact of biomass feedstock (11) and pressurized hot water (15), to separate lignin component and hemicellulose component from biomass. The supply path of biomass feedstock and pressurized hot water from respective supply unit (31) into reaction apparatus is switched, and hydrothermal decomposition reaction is performed, and biomass solid content (17) is discharged after completion of reaction. A rotary switching mechanism continuously performs supply, reaction and extraction of biomass.    USE - Hydrothermal decomposition-reaction system of biomass used for manufacturing system of organic raw material such as alcohol, petroleum substituent and amino acid (all claimed) used as foodstuff or feed raw material. Can also be used for manufacturing liquefied petroleum gas, aircraft jet fuel, kerosene, diesel oil, fuel oil, naphtha, ethylene glycol, ethanolamine, vinyl chloride polymer, vinyl acetate emulsion, polystyrene, polyethylene, polycarbonate, methyl methacrylate resin, nylon and polyester.    ADVANTAGE - The sugar components can be recovered efficiently as the excessive addition of solution to the hemicellulose component is suppressed by carrying out opposition contact of biomass feedstock with pressurized hot water. The sugar liquid can be efficiently saccharified, and various organic raw materials can be manufactured efficiently on the basis of the sugar liquid.    DETAILED DESCRIPTION - The reaction temperature of hydrothermal decomposition apparatus is set to 180-240 degrees C. The weight ratio of the biomass feedstock and pressurized hot water is set in the range of 1/1-1/10. An INDEPENDENT CLAIM is included for manufacturing system of organic raw material using biomass feedstock, which has pre-processor to pre-process biomass feedstock, enzymatic-decomposition apparatus that performs enzyme-treatment of cellulose in biomass solid content discharged from hydrothermal decomposition apparatus, and decomposes to sugar liquid that contains hexose. Another enzymatic-decomposition apparatus performs enzyme-treatment of hemicellulose components in discharged hot-water (16), and decomposes to sugar liquid that contains pentose. A fermentation apparatus performs fermentation of sugar liquid obtained from enzymatic-decomposition apparatus, to manufacture alcohol, petroleum substitute item or amino acids.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the hydrothermal decomposition-reaction system. (Drawing includes non-English language text)    Biomass feedstock (11)    Pressurized hot water (15)    Discharged hot-water (16)    Biomass solid content (17)    Supply unit (31)    Hydrothermal decomposition apparatus (41)