A saccharide-solution production method using a biomass material, including feeding a biomass material containing cellulose, hemicellulose, and lignin under a normal pressure to put it under an increased pressure; hydrothermally decomposing the biomass material using pressurized hot water by a hydrothermal decomposition unit; and dissolving a lignin component and a hemicellulose component in the pressurized hot water; thereafter, adding a biomass solid discharged from the hydrothermal decomposition unit to a slurrying vessel containing water injected therein and communicating with the hydrothermal decomposition unit so as to obtain a slurried biomass solid; then, removing water from the slurried biomass solid; and thereafter, performing enzymatic saccharification of the water-removed biomass solid to produce a saccharide solution.