The primary purpose of the present invention is to provide a water-absorbing resin that has excellent liquid permeability while also having an appropriate absorption capacity and that is ideal for use in an absorbent article for use as a sanitary material or the like. The present invention is a water-absorbing resin formed by reverse-phase suspension polymerization of a water-soluble ethylenic unsaturated monomer in the presence of a dispersion stabilizer to obtain primary particles and causing these particles to coagulate by means of additional reverse-phase suspension polymerization, wherein the water-absorbing resin is characterized in that the median grain size of the primary particles is 100 to 250 [mu]m and the physiological saline-retaining capability of the water-absorbing resin is 30 g/g or less.