Method of producing sugar liquid

A method of producing a sugar liquid from cellulose-containing biomass comprising (1) to (3):

• (1):
• subjecting a cellulose-containing biomass to hydrothermal treatment and thereafter separating the treated cellulose-containing biomass into a hydrothermally-treated liquid and a cellulose-containing solid content;
• (2):
• adding a filamentous fungus-derived cellulase to the cellulose-containing solid content obtained in (1) to hydrolyze the cellulose and thereafter separating the hydrolysate into a saccharification residue and a sugar liquid;
• and
• (3):
• washing the saccharification residue obtained in the step (2) with the hydrothermally-treated liquid obtained in (1) to elute the filamentous fungus-derived cellulase adsorbed to the saccharification residue into the hydrothermally-treated liquid and thereafter obtaining a solution component comprising the filamentous fungus-derived cellulase by solid-liquid separation,
• wherein the hydrothermally-treated liquid used in the step (3) comprises enzymatic saccharification inhibitors.