PURPOSE: To obtain a saponin component with a small amount of a solvent used economically in high yield, by using soybean germ as a raw material, pretreating it, extracting it with a solvent.

CONSTITUTION: For example, soybean germ is ground, treated with n-hexane, and further de-fatted with methylene chloride. Then, a solvent (preferably methanol) is added to it, it is stirred under heating to extract all the saponin component. The solution is then filtered to remove the extraction residue, the extracted solution is dried under reduced pressure to remove the solvent, so that the saponin component is obtained.