The present invention is to provide a new surfactant that can be used as an emulsifier excellent in emulsion stability and texture in use and as a cleanser excellent in cleansing power and texture in use and having low skin irritation.
A surfactant consisting of a compound represented by the below-described general formula (1).

        Y-O-(EO) l -(AO) m -(EO) n -X     (1)

(In the formula, AO represents an oxyalkylene group having 3 to 4 carbon atoms; m is the average addition mole number of the oxyalkylene group and satisfies 5≦m≦100. EO represents an oxyethylene group; 1 and n are the average addition mole numbers of the oxyethylene groups and satisfy 0≦1≦4 and 0≦n≦4. Either X or Y or both are a functional group represented by -SO 3 M, -COOM, -HPO 3 M, -(CH 2 ) q -SO 3 M, or -(CH 2 ) q -COO, wherein M is a hydrogen ion or a monovalent inorganic or organic cation, and q is the number of carbon atoms of the linked alkylene group and satisfies 1≦q≦4. When either X or Y is the above-described functional group, the other one can be a hydrogen atom, a methyl group, or an ethyl group.)