To provide an anionic surfactant which, less in the content of organically bound halogens than the conventional ones, is safe for the environment and human body.

The anionic surfactant, which has a content of the organically bound halogens of ≤0.2 wt%, is obtained by causing an organic compound containing a hydroxy group (a) (mentioned below) to form a sulfuric acid ester in the presence of a hydrocarbon solvent such as an aliphatic saturated hydrocarbon and an alicyclic saturated hydrocarbon. The organic compound containing a hydroxy group (a) includes a mixture aliphatic alcohol consisting of one or more organic compounds containing a hydroxy group, an addition product of an aliphatic alcohol with an alkylene oxide, an addition product of an aliphatic carboxylic acid with an alkylene oxide, and an addition product of an alkyl phenol with an alkylene oxide.