Reversed phase suspension polymerization is allowed while controlling content of minor components in monomer, particularly controlling a content of acetic acid and propionic acid being not higher than 500 ppm, controlling a content of acrylic acid dimer being not higher than 1000 ppm, in acrylic acid. Cross-linked polymer obtained by the polymerization is subjected to a surface crosslinking treatment without substantially using an organic solvent, and under heating at high temperature (150° C. or higher and 250° C. or lower). Thereafter, agglomeration is carried out without substantially using an organic solvent. Accordingly, a particulate water-absorbing agent including a water-absorbing resin having superior property, and being suited for practical applications at high concentrations in absorbing cores such as a diaper and the like without generation of any odor of the organic solvent can be obtained because no volatile organic compound is included.
