There is provided a surfactant composition for detergents, which has its high detergency and foamability within a broad pH region even in the presence of solids. It has its excellent foamability, thickening property, water solubility and stability. The composition contains a component (a) represented by the following formula (I) and at least one component (b) represented by the formulae (II) and (III), in the total amount of 0.1 to 80% by weight, at the ratio of (a)/(b) by weight of from 99.9/0.1 to 70/30.
1
In the formula (I), R
1
CO— is a saturated or unsaturated acyl group which has 6 to 24 carbon atoms and which may have hydroxy group; R
2
is a linear or branched alkyl group having 1 to 3 carbon atoms; and R
3
is a linear or branched alkylene or alkenylene group having 1 to 6 carbon atoms.
2
In the formulae (II) and (III), R
1
CO—, R
2
and R
3
have the same meanings as above and R
4
CO— is a saturated or unsaturated acyl group which has 6 to 24 carbon atoms and which may have a hydroxy group. The composition may also contain a surfactant other than the above-mentioned components (a) and (b).