Wildbean(Glycine soja Siebold et Zucc.) is known as the orgin of soybean (Glycine max Merr.). Based on the hypothesis that the secondary transformation of chemical compound in wildbean might have occurred during its breed improvement to soybean. this study was carried out to compare the antioxidant activities and chemical composition in wildbean and soybean. The present study demonstrates that 1) Antioxidant activity was much higher in EtOAc, extract of wildbean than in soybean. 2) strong antioxidant activity observed in EtOAc extract of wildbean was due to the presence of (-)-epicatechin, which was not present in the extract of soybean but isolated, for the first time, from the extract of wild bean, and 3) antioxidant activity of the isolated (-)-epicatechin was greater than that of tocopherol, the previously known antioxidant.