The present invention provides a process for producing a highly unsaturated fatty acid-containing lipid which is less expensive than existing ones, which comprises culturing a microorganism belonging to the genus Mortierella with the use of, as a medium carbon source, a saccharified starch, which is less expensive than glucose, does not contribute to an increase in osmotic pressure of the culture medium, and can be utilized by the Mortierella microorganism, and collecting a highly unsaturated fatty acid-containing lipid from the culture.