In order to obtain basal data for industrial application of inulinase from Bacillus sphaeicus 188-1, its intracellular inulinase was purified by ammonium sulfate fractionation and column chromatography on DEAE-Sephadex A-50 and Sephadex G-100. The enzyme was homogeneous as judged by SDS-polyacrylamide gel electrophoresis, with an apparent molecular weight of 29 kDa. Inulinase activity was optimal at pH 6.5 and 4$0^{circ}C$. The enzyme activity was significantly inhibited by Cu$^{2＋}$, Cd$^{2＋}$ and Hg$^{2＋}$. The inulinase exhibited an apparent Km value of 0.014% for inulin.