Hydrolysis of trisaccharides consisting of different monosaccharides, such as 1-kestose, melezitose, raffinose and lactosucrose, was performed in the subcritical water in a temperature range of 150 to 230°C at 10 MPa. The hydrolysis of each trisaccharide proceeded consecutively. For all the trisaccharides, one of the two glycosidic bonds was preferentially hydrolyzed and the produced disaccharide was then hydrolyzed. The hydrolyses of trisaccharides except when the substrate contained β-Fru(2→ 1)β-Fru or α-Glc-(→ 2)β-Fru bond and their constituent disaccharides were expressed by the first-order kinetics of the substrate concentration. The hydrolysis of maltooligosaccharides with the degree of plomerization (DP) of 2 to 6 in the subcritical water also proceeded consecutively. The first-order kinetics was applicable for the decrease of the substrate at short residence times in the tubular reactor. The changes in the concentration of the substrate and maltooligosaccharides with the DPs shorter than the DP of the substrate were calculated by solving the mass balance equations for the saccharides simultaneously. The calculated curves expressed well the experimental results at the short residence times but deviated from the results at the longer residence times. There was site-specificity in the hydrolysis, and the rate constants for exo-site glucosidic bond were slightly greater than those for the endo-site bond.