Provided is a method for producing a water absorbent resin, which promotes the formation of interconnected voids (continuous gas bubbles) in a foamed polymer (foam-like water absorbent resin) by a more convenient method, and produces with high efficiency a water absorbent resin which exhibits a high water absorption rate even when stepped into a sheet form or a powder form in hygiene articles and the like. Disclosed is a a method for producing a polyacrylic acid-type water absorbent resin, comprising (A) a step of obtaining an aqueous solution of acrylic acid-type monomers containing gas bubbles dispersed therein； (B) a step of polymerizing the aqueous monomer solution and thereby obtaining a foamed polymer； and (C) a step of heating and drying the foamed polymer, wherein gas bubbles are incorporated such that the volumetric expansion factor defined by the following formula (1)； [Formula 1] exceeds 1.1 times, and the aqueous monomer solution having a monomer concentration defined by the following formula (2) ； [Formula 2] of 40% by weight or greater is boiling temperature of 100°C or higher.
