A co-modified organopolysiloxane represented by General Formula (1): R2R12SiO(R12SiO)nSiR12Q, and a surfactant/dispersing agent, emulsifier for a water-in-oil emulsion, external use preparation and cosmetic composition comprising the same. In the formula, the R1 groups are monovalent hydrocarbon group having 1 to 12 carbon atoms, R2 is a monovalent hydrocarbon group having 13 to 30 carbon atoms, and Q is a sugar alcohol group-containing organic group or a diglycerin derivative group having an average number of repetitions of a glycerin unit of 1.1 to 2.9, n is a number in a range of 0 to 100.
