To elucidate enzymatic properties of ${alpha}-galactosidase$ (EC 3, 2, 1, 22) from germinated soybean, changes in the enzyme activities and oligosaccharide contents during germination of soybean were determined. ${alpha}-Galactosidase$ from germinated soybean was purified by ammonium sulfate fractionation, ion exchange chromatography and gel filtration. Their chemical and enzymatic properties was investigated. ${alpha}-galactosidase$ activity of sobeam was maximized when it was germinated at $25^{circ}C$ for 120 hour. Raffinose and stachyose in soybean were decomposed completely after 96 hours and 120 hours of germination, respectively. Soybean ${alpha}-galactosidase$ was purified by 6.6 fold by ammonium sulfate fractionation, ion exchange chromatography on DEAE-Cellulose and Sephadex A-50, and gel filtration on Sephadex G-150. Its specific activity was 825 Units/mg protein and the yield was 2.5% of the total activity of crude extracts. The purified ${alpha}-galactosidase$ of soybean was found to be homogeneous by polyacrylamide gel electrophoresis and by HPLC. Isoelectric point of soybean ${alpha}-galactosidase$ was determined analytical isoelectric focusing to be pH 4.8. The soybean ${alpha}-galactosidase$ was monomeric and its molecular weight was estimated to be 30,000 by SDS-PAGE. The optimal temperature and pH for the soybeam ${alpha}-galactosidase$ activity were $40^{circ}C$ and pH 6.0 and 75% of its activity was lost by heating at $60^{circ}C$ for 10 min. The enzyme was appeared to have higher affinity to raffinose than to stachyose. The Km value of soybean enzyme was 5.3 mM for ${ ho}-nitrophenyl-{alpha}-D-galactopyranoside$ and the activation energy on PNPG was calculated to be 13.02 Kcal per mole.