A process for producing Surfactin, comprising culturing a microorganism of the genus Bacillus in a liquid culture medium containing flour of beans such as soybean or an extract thereof as a nitrogen source and accumulating Surfactin in the culture broth, and a microorganism of the genus Bacillus which have an activity to produce a crude Surfactin in a concentration of from 8 to 50 g/L on culturing for 20 to 90 hours.