Sugi (cryptomeria japonica D. Don) wood meal was extracted with subcritical water in a semi-batch reactor. About 70-90% by weight of the sugi wood meal was converted into water-soluble compounds. The main components of the water-soluble compounds were monosaccharides and oligosaccharides, as a result of hydrolysis of cellulose and hemicellulose. White precipitates appeared in the solution after settling for 48 h. X-ray diffractometry clearly showed that precipitates had crystallized into cellulose II. High yield of total saccharides (including the precipitates) was obtained at 310-320 degrees C, 25 MPa and 65 g min(-1) water flow rate from a wood meal charge of 2.0 g, while the decomposition reaction was completed within about 20 min. Moreover, the yield increased to more than 60% when the wood meal was pretreated for improved wettability. It is shown that saccharides can be produced from sugi wood powder quickly and effectively by treatment in suberitical water. (C) 2007 Elsevier B.V. All rights reserved.