The present invention relates to a water absorbing resin which increases the diffusivity of a liquid to be absorbed and which makes it possible to effectively decrease the amount of re-humidification. The water-absorbent resin is obtained by polymerization of a water-soluble ethylenically unsaturated monomer under the presence of an internal cross-linking agent, has the capacity of water absorption of physiological solution under a charge of 4.14 kpa at 120 minutes since the onset of water absorption of 20 ml / g or more and exhibits the degree of swelling under a 30 minute load of 70% or less when the water absorption capacity of saline under a charge of 4.14 kpa at 120 ° C Minutes from the onset of water absorption is designated as the degree of swelling under a 100% load. The water-absorbent resin may be produced by performing the following steps in a method in which a water-absorbent resin is produced by performing reverse phase suspension polymerization of a water-insoluble ethylenically unsaturated monomer in a hydrocarbon dispersion medium under the composition. Presence of a cross-linking agent: a step in which polymerization is carried out under the presence of a nitrogen-based compound and a peroxide； and a step in which a water-containing gel obtained by said polymerization is post cross-linked using a post cross-linking agent.a presente invenção refere-se a uma resina absorvente de água que aumenta a difusividade de um líquido a ser absorvido e que torna possível diminuir efetivamente a quantidade de re-umidificação. a resina absorvente de água é obtida por polimerização de um monômero etilenicamente insaturado solúvel em água sob a presença de um agente de reticulação interna, tem a capacidade de absorção de água de solução fisiológica sob uma carga de 4,14 kpa a 120 minutos passados desde o início da absorção de água de 20 ml/g ou mais e exibe o grau de intumescimento sob uma carga a 30 minutos de 70% ou menos quando a capacidade de absorção de água de
