To provide a surface active agent composition which excels in flowability at a high concentration and, simultaneously, at a low viscosity, and contains a phosphoric acid ester salt of an organic hydroxy compound, and its manufacturing method.

The surface active agent composition comprises (a) 50-90 wt.% phosphoric acid ester salt of an organic hydroxy compound to be represented by formula (I): RO(AO)nH (wherein R is an 8-24C alkyl group or an alkenyl group; A is a 2-4C alkylene group; and n is a number of 0-20), (b) 1-8 wt.% 1-3C monohydric alcohol, and (c) 1-30 wt.% at least one compound to be selected from the group consisting of 1-3C polyhydric alcohols and polyalkylene glycols having a molecular weight of ≤5,000, and has a viscosity at 30°C and at a shear rate of 50 s-1 of ≤3,000 mPa.s, and its manufacturing method is disclosed.