Enzymatic saccharifications of the hydrolysate collected as the water-soluble (WS) portion after hot-compressed water (HCW) treatment of Japanese beech with xylanase and β-xylosidase were performed to investigate the hydrolytic properties of these enzymes. The WS portions with different molecular weight distributions and initial concentrations of xylooligosaccharides were prepared as substrates, one of which contained mainly smaller xylooligosaccharides [degree of polymerization (DP) = 2 or 3], while the other contained larger xylooligosaccharides (DP ≥ 4). The highest xylose recovery was obtained from both of the WS portions treated with β-xylosidase rather than with xylanase. This suggests that β-xylosidase could have a higher activity than xylanase toward larger xylooligosaccharides (DP ≥ 4) as well as smaller xylooligosaccharides (DP = 2 or 3) recovered from HCW treatment. As a result, the use of β-xylosidase was found to be effective for saccharifi cation of the WS portion, even with a short reaction time for the HCW treatment.