To provide a method for bleaching a surfactant soln. which can efficiently bleach an aq. surfactant soln. and can provide a very pale, odor-free product having excellent color stability under mild conditions by comprising treating a concentrated aq. surfactant soln. with hydrogen peroxide or the like under specified conditions.

In bleaching a concentrated aq. soln. of a surfactant, such as an alkyl polyglycoside, having a pH value of 7 to 10, in the first stage, oxidation bleaching is carried out using hydrogen peroxide as a bleaching agent in the presence of a stabilizer using an inorg. magnesium compd. in an amt. of 50 to 10,000 ppm (based on the surfactant). After optional predecomposition of the peroxide using a transition metal (compd.) over a catalyst provided in the intermediate position, in the second stage, excess, unreacted bleaching agent and/or oxidizing secondary products produced therefrom are removed by the addition of an enzyme having catalytic activity, such as catalase, pref. in an amt. of 0.1 to 5,000 ppm to bleach a concentrated aq. surfactant soln.