We found a bacterium that converts sucrose to a useful material, using about 6,000 samples of bacteria isolated from soil. This bacterium, Bacillus sp. 217C-11, was identified according to Bergey's manual, and produced a highly efficient enzyme that converted sucrose into inulin. So, the enzyme was purified to homogeneity through five chromatographic steps, to identify its enzymatic properties. The molecular mass of the enzyme was estimated to be 45,000, and this enzyme was a monomer protein (by SDS-PAGE). The optimum pH and temperature of this enzyme were 7-8 and 45-50 degrees C, respectively. The enzyme reacted only with sucrose, but did not with other disaccharides, fructooligosaccharides and inulin. This paper will show that our enzyme is a novel one, which is different from the other well-known enzymes concerned in inulin production.