A compound represented by the following general formula (I), wherein R.sup.1 and R.sup.2 represent a hydrocarbon group having 1 to 26 carbon atoms, preferably a linear or branched alkyl group, R.sup.3 represents a hydrocarbon group having 7 to 10 carbon atoms, preferably a linear or branched alkyl group, n represents 1 or 2 provided that the acidic amino acid residue in the molecule is L-aspartic acid residue when n is 1 and said acidic amino acid residue is L-glutamic acid residue when n is 2, and a gelling agent for an oil comprising said compound ##STR00001##