A water-absorbing resin has a polymer molecular chain in which 50 mol % or more of repeating units in the chain are carboxy group-containing units, wherein the carboxy group neutralization ratio in the central part of the resin is 60 mol % or more and the carboxy group neutralization ratio on the external surface of the resin is 50 mol % or less. A method for producing the water-absorbing resin comprises polymerizing a monomer solution to form a polymer, drying the resulting polymer, and heat-treating the dried polymer, wherein the monomer solution contains a mixture comprising an alkali metal salt of an unsaturated carboxylic acid and an ammonium salt thereof, the percentage of the ammonium salt being more than 50 mol % of the mixture, and further contains a condensation crosslinking agent.