▎ 摘　　要

NOVELTY - A hydrolysis catalyst comprises a graphene sheet comprising a sheet formed by connecting carbon skeletons having carbon atoms bonded to each other in a hexagonal shape in a plane. The graphene sheets are laminated in 2-5 layers. In the graphene sheet, 1 or more carboxyl group and sulfonic acid group is bonded. The length of the shortest portion of the graphene sheet in a photograph taken by the transmission electron microscope is 1 mu m or more. USE - Catalyst is used for hydrolyzing cellulose and hemicellulose for producing monosaccharide (claimed). ADVANTAGE - The catalyst is environmentally-friendly, and enables efficient of hydrolyzing cellulose and hemicelluloses. The catalyst can be separated from hydrolyzed mixture by simple process. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) manufacture of hydrolysis catalyst, which involves mixing flaky graphite, sulfuric acid and hydrogen peroxide solutions, heat-treating resultant mixture at 500-1000 degrees C, cooling, and heat-treating at 500-1000 degrees C; (2) usage method of hydrolysis catalyst for producing monosaccharide, which involves hydrolyzing cellulose and/or hemicellulose in water, subjecting resultant solution to membrane filtration and separating the catalyst; and (3) device for manufacturing sugar-containing liquid.