A method of manufacturing Cassia tora L. extract having anti-obesity effect is provided to obtain the Cassia tora L. extract having excellent anti-obesity effect by inhibiting enzymatic activity by subjecting raw Cassia tora L. extract to a column chromatography filled with silica gel and fractionating it. Raw Cassia tora L. is dried, extracted with 99% alcohol such as methanol or ethanol at 30 to 60deg.C for 1 to 3 weeks, subjected to a column chromatography filled with silica gel and fractionated into 10 fractions. Then, any one of the 6th and 7th fractions is collected, additionally subjected to a column chromatography filled with silica gel and fractionated into 16 fractions. Then, any one of the 7th and 10th fractions is collected.
