To obtain a polyoxyalkylene fatty acid amide sulfuric acid ester salt useful as a surfactant excellent in color stability in storage and low in skin stimulating property.

This polyoxyalkylene fatty acid amide sulfuric acid ester salt of a compound of formula II [X is an alkali metal, an alkaline earth metal, etc. ; (p) is the same as the valence number of X] is obtained by performing a sulfurization reaction and a neutralization reaction on a polyoxyalkylene fatty acid amide of formula I [R1 is a 7-21C alkyl or an alkenyl; R2 is H or CH3; (m), (n) are each ≥0 and (m+n)=1-30]. In this case, at least one kind selected from a reducing agent of the formula: M(BH4). [M is an alkali metal, Ca, Zn or (CH3)4N; (x) is 1, 2] and an antioxidant (e.g.; dibutylhydroxytoluene) is added for performing the reaction. The amount of addition is 0.001-5wt.% based on the compound of the formula I.