Polyacrylic acid (salt) -based water-absorbing resin and its manufacturing method

[Object] is provided a method for producing a water absorbent resin and a polyacrylic acid (salt) -based, the amount of residual monomer is reduced, the water-absorbing resin and adapted to a simple method of manufacturing absorbent bodies used in practical use. [Solution] (salt) -based water absorbent resin production method, which is a polyacrylic acid comprising the following steps (salt) -based water-absorbent resin production method of a polyacrylic acid: will acrylic acid (salt) as a main component a single aqueous solution polymerization of the polymerization step thereof, the polymerization step is obtained hydrogel crosslinked polymer was dried in the drying step, the drying or after the surface crosslinking step of drying the water-absorbing resin surface crosslinked, and a after the surface-crosslinked water-absorbent resin package packaging step, the iron component content in the above aqueous monomer solution in the polymerization step the monomer is 2ppm or less, the above-mentioned packaging step is an aqueous water-absorbing resin was 1 wt% above, the above-described method, after the packaging step, further comprising the water-absorbing resin after the package is stored over three days storage process.