Method for producing water-absorbent resin

[Problem] To provide a method for producing a water-absorbent resin with which the resulting water-absorbent resin has a high water absorbency without pressure and with which it is possible to efficiently obtain a water-absorbent resin. [Solution] A method for producing a water-absorbent resin, said method comprising: a polymerization step for obtaining a water-containing gel-like crosslinked polymer by polymerizing a monomer composition containing an internal crosslinking agent and a monomer; and a drying step for drying the aqueous gel-like cross-linked polymer to obtain a dried polymer, the aqueous gel-like cross-linked polymer supplied in the drying step containing hydrogen peroxide in an amount of 50 ppm or more relative to the solid content mass of the aqueous gel-like cross-linked polymer, and in the drying step, the aqueous gel-like cross-linked polymer contains hydrogen peroxide in an amount of 50 ppm or more relative to the solid content mass of the aqueous gel-like cross-linked polymer. The heating