PURPOSE: To provide a detergent which gives an excellent use feeling after cleansing and is satisfactory in cleansing ability and long-term stability by incorporating a fatty acid ester modified with maleic anhydride and an anionic sulfate or sulfonate surfactant in specific amounts.

CONSTITUTION: (A) Either a fatty acid ester modified with maleic anhydride or a salt thereof and (B) an anionic sulfate or sulfonate surfactant are incorporated in such amounts that the sum of (A) and (B) is 5-60wt.% and the (A)/(B) ratio is 20/1 to 1/20 by weight to produce a detergent. The ingredient (A) is produced by reacting an unsaturated fatty acid, preferably a 10-26C one, with a 1-4C alcohol, causing maleic anhydride to add the resulting ester, and then hydrolyzing and hydrogenating the adduct. This detergent is less irritating, is excellent in foaming property and use feeling, and has good long-term stability.