A detergent composition comprising: (1) a surface active agent or a water-soluble polymeric compound and (2) a polymer which contains recurring units (I-1) and (I-2). (I-1) (I-2) wherein R1 is a hydrogen or a methyl or ethyl group, R2 represents an alkyl, aryl or aralkyl group having 4-15 carbon atoms. The detergent composition exhibits extremely reduced irritation to the skin and the hair, possesses outstanding detergency and foaming and foam-breaking capability, and imparts an excellent feeling upon use.