The present invention provides a method for producing water-absorbing resin particles having high equilibrium swelling capacity, a high water-absorption rate or high initial swelling capacity, and an appropriate particle size that achieves good handling performance； water-absorbing resin particles obtained by the method； and a water blocking material and an absorbent article which include the water-absorbing resin particles. The present invention is a method for producing water-absorbing resin particles, which comprises: preparing a hydrogel polymer by reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a hydrocarbon solvent in the absence of an internal crosslinking agent but in the presence of a surfactant with an HLB of 8 to 12； carrying out a post-crosslinking reaction of the hydrogel polymer whose moisture content is adjusted to 30 to 110 mass% based on a water-soluble ethylenically unsaturated monomer component that composes the hydrogel polymer.本發明提供一種具有較高之平衡膨潤(equilibrium swelling)性能，同時具有優異之吸水速度及較快之初期膨潤性能，且粒徑適宜，操作性良好之吸水性樹脂粒子之製造方法；藉由該製造方法獲得之吸水性樹脂粒子；使用該吸水性樹脂粒子之防水材料及吸收性物品。本發明係一種吸水性樹脂粒子之製造方法，其具有以下步驟：藉由於不存在內部交聯劑、存在HLB為8～12之界面活性劑之條件下，使水溶性乙烯性不飽和單體於烴溶劑中逆相懸浮聚合，而製備含水凝膠狀聚合物之步驟；及相對於構成上述含水凝膠狀聚合物之水溶性乙烯性不飽和單體成分，將上述含水凝膠狀聚合物之含水率調整為30～110質量%之後，進行後交聯反應之步驟。
