To provide an anionic surfactant powder comprising a polyoxyalkylene ether sulfate which powder has high stability in hard water, high low-temperature solubility and is improved in powder characteristics such as caking characteristics, and a method of producing the anionic surfactant powder. An anionic surfactant powder comprising polyoxyalkylene alkyl ether sulfates in which the average addition mol number of alkylene oxides is 0.05 to 2, wherein the content of the polyoxyalkylene alkyl ether sulfates provided with alkylene oxides added thereto in an amount of 4 mol or more is 30 % by weight or less based on the total anionic surfactant, an anionic surfactant powder further comprising a water-soluble inorganic salt, a method of producing each of these anionic surfactant powders, and a detergent composition and a cement additive comprising these anionic surfactant powders.