PURPOSE: To obtain the subject composition containing an α-sulfo fatty acid derivative and a fatty acid diethanolamide in a specified ratio, excellent in foamability, hard water resistance and washing performance at low concentrations, and useful as a detergent for tableware, etc.

CONSTITUTION: This liquid detergent composition contains (A) 1-30wt.% of an α-sulfo fatty acid derivative of formula I (R1, R2 are each 6-18C alkyl, alkenyl; M1, M2 are each H, alkali metal, etc.; A1 is alkylene, etc.; (m) is 1-50) and/or formula II (R3 is 6-18C alkyl, alkenyl; M3 is H, alkali metal, etc.; A2 is alkylene, etc.; (n) is 1-50) and (B) 1-10vol.% of a fatty acid diethanolamide of formula III (R4 is 7-15C alkyl, alkenyl; (p), (q) are each 1-4 which express the average addition molar numbers of C2H4O).