A process for producing a glycolipid ester represented by the formula, ##STR1## wherein R.sub.3 represents a hydrogen atom or a methyl group, R.sub.4 represents a saturated or unsaturated hydrocarbon group having 12 to 16 carbon atoms when R.sub.3 is a hydrogen atom, R.sub.4 represents a saturated or unsaturated hydrocarbon group having 11 to 15 carbon atoms when R.sub.3 is a methyl group, and R represents a saturated or unsaturated alkyl group having 2 to 20 carbon atoms, which comprises subjecting Sophorolipid to methanolysis and methylation reactions by reaction with methanol in the presence of a strong acid to produce methyl 1-[(2'-O-.beta.-D-glucopyranosyl-.beta.-D-glucopyranosyl)oxy]-alkanoate and -alkenoate, and subjecting the resulting mixture to ester interchange by reaction with an alcohol represented by the formula,ROHwherein R is the same as defined above.