NOVELTY - Enzyme reactor comprises outer cylindrical tank formed by obstructing both ends, inner cylindrical tank formed by obstructing both ends and accommodated in the outer tank, stirrer provided in the inner tank for making stirring flow in the perpendicular direction, supply unit for supplying biomass processed material and saccharogenic amylase to the inner tank, filter provided in a portion of at least bottom portion of the inner tank, and liquid discharge port formed in the bottom portion of the outer tank.    USE - The enzyme reactor is useful for decomposing biomass processed material containing cellulose and lignin using saccharogenic amylase and decomposing cellulose into water-soluble sugar content, and in cellulose saccharification device used in biomass saccharification device used in ethanol production device for producing ethanol (all claimed).    ADVANTAGE - The enzyme reactor improves yield of sugar content, thus reduces cost of ethanol production, increases concentration of cellulose, and allows efficient mixing of to-be-processed components. The ethanol production device produces highly purified ethanol.    DETAILED DESCRIPTION - Enzyme reactor comprises outer cylindrical tank (40) formed by obstructing both ends, inner cylindrical tank (41) formed by obstructing both ends and accommodated in the outer tank, where the inner tank and the outer tank are arranged horizontally such that the central axis faces horizontal direction, stirrer (44) provided in the inner tank for making stirring flow in the perpendicular direction, supply unit (46) for supplying biomass processed material and saccharogenic amylase to the inner tank, filter (43) provided in a portion of at least bottom portion of the inner tank, and liquid discharge port (47) formed in the bottom portion of the outer tank. INDEPENDENT CLAIMS are included for the following:    (1) cellulose saccharification device , comprising the above-mentioned enzyme reactor, and first catalytic reactor decomposing degradation products produced in the enzyme reactor into glucose using solid acid catalyst;    (2) biomass saccharification device , comprising pressurized hot water reaction device which selectively decomposes hemicellulose contained in the biomass by pressurized action of hot water, solid-liquid separator for separating cellulose and lignin as solid from the processing liquid of the pressurized hot water reaction device , and cellulose saccharification device for decomposing the cellulose in the solid portion separated by the solid-liquid separation device into glucose; and    (3) ethanol production device , comprising the above-mentioned biomass saccharification device , first fermentation device generating ethanol from glucose produced by the biomass saccharification device , second fermentation device producing ethanol from the monosaccharide hemicellulose derived from the biomass saccharification device .    DESCRIPTION OF DRAWING(S) - The drawing shows schematic structure of enzyme reactor.    Outer tank (40)    Inner tank (41)    Filter (43)    Stirrer (44)    Heating unit (45)    Supply unit (46)    Liquid discharge port (47)    Solid portion outlet tube (48)