PURPOSE: To obtain a stabilized titled compound having extremely little variation of quality with time, by adding a neutralizing agent consisting of lactic acid and/or lactic acid salt to a phenol ethoxylate produced by reacting a phenolic compound with ethylene oxide and sulfating the mixture.

CONSTITUTION: Ethylene oxide is added to a phenolic compound such as nonylphenol, octylphenol, etc., to obtain a phenol ethoxylate, which is added with a neutralizing agent consisting of lactic acid and/or lactic acid salt (especially preferably sodium lactate or potassium lactate). The amount of the lactic acid, etc., is 5W0.001pts.(wt.), preferably 1W0.05pts. per 100pts. of the phenol ethoxylate. The mixture is sulfated to obtain the objective stabilized phenol ethoxysulfate having extremely little generation of odor with time.

USE: A surfactant.