An object of the present invention is to provide a water absorbing agent having a low amount of residual monomer, small variance of the amount of residual monomer among ranges of particle size distribution and favorable absorption properties, and being sanitary an absorbing article and a method for the production of a water absorbing agent. The water absorbing agent of the present invention has the amount of residual monomer of not higher than 500 ppm, and a residual monomer index of not greater than 0.30.The method for the production includes a first step of obtaining a hydrogel polymer by polymerizing an aqueous solution of a monomer including an unsaturated carboxylic acid and/or a salt thereof in the presence of a crosslinking agenta second step of obtaining a water absorbent resin precursor which is in powder form and includes particles having a particle size of 300 to 850 µm and particles having a particle size of smaller than 300 µm as main components by drying said hydrogel polymer followed by pulverization and classification to adjust the particle size distribution,a third step of obtaining a water absorbent resin by heating a mixture of said water absorbent resin precursor and a surface crosslinking agent, which can form an ester bond around the surface of said water absorbent resin precursor,a fourth step of adding by spraying an aqueous solution that includes a sulfur-containing reducing agent to said water absorbent resin, and a fifth step of subjecting the mixture of the water absorbent resin and said aqueous solution to a heat treatment under an airflow of not lower than 40°C but not higher than 120°C.La présente invention a pour objet un agent d’absorption d’eau présentant une faible quantité de monomère résiduel, un léger écart de la quantité de monomère résiduel parmi les séries de distributions granulométriques et des propriétés d’absorption favorables, et qui est hygiénique un article absorbant et un procédé de production de cet agent d’absorpt
