Previous studies1- in our laboratory have shown that some strains of Aspergillus niger and Rhizopus delemar and some other fungi produced a great deal of lipase, It has been proved that the physicochemical properties and the substrate specificity of lipases 0:'tained from different organisms were quite different from each other. Further experiment was undertaken for research on a novel type of lipase. From the results, a strain of Fungi imperfecti was selected as an efficient lipase producer among 1200 strains of the microorganism isolated from the air, the soil and clotted vegetables and foods. It was also found that this organism required a special component such as lipid in the medium for its lipase production. The microorganism was identified as Geotrichlllll candidllJll Link. * Lipase production by Geotriclllllll candidulI1 has already been reported, 5 61 however, according to the papers, it was clarified that the microorg:mism produced lipase constitutively in a medium without lipid. Therefore, the study was carried out on the lipid requirement for the lipase production by the microorganism selected by our screening test. Lipase activity was assayed by the method as described in the previous paper. 21 Enzyme activity which liberated one microgram equivalent of fatty acid from the substrate, olive oil, per one minute was defined as one unit (U). Although the organism grew well in the all media shown in Table J, the presence of rice bran in the medium seemed to be essential for the lipase production. Using the other media without rice bran, lipase activity was detected neither in the culture broths nor in the cells at any phase of the growth. It was observed that lipase production increased with the concentration of the rice bran in the medium. Although the attempt was made to find a relation between lipase productivity and variety of carbon source or nitrogen source such as peptone, glucose, corn steep liquor