Disclosed is a method for producing a xylo-oligosaccharide from a biomass containing xylan and cellulose, wherein the method is simple and a high xylo-oligosaccharide yield is achieved by suppressing xylo-oligosaccharide from being broken down to xylose. According to the method for producing xylo-oligosaccharide, a biomass containing xylan and cellulose is hydrolyzed by a cellulase composition that, at the time of hydrolysis, at least exhibits xylanase, cellobiohydrolase, and β-glucosidase activities, but does not substantially exhibit β-xylosidase activity.
