Provided are: a water-absorbing resin which has an excellent water absorption performance and with which it is possible to improve absorption performance under a load when used in an absorbent body； and an absorbent article using an absorbent body that includes the water-absorbing resin. This water-absorbing resin, obtained by polymerising a water soluble ethylenically unsaturated monomer in the presence of an internal crosslinking agent and by post-crosslinking using a post-crosslinking agent, has a physiological saline absorption capacity of 16 mL/g or more under a load of 4.14 kPa, has a mass ratio of 85 mass% or more of 150-850 [mu]m particles that account for a proportion of the entire water-absorbing resin, moreover has a mass ratio of 20 mass% or more of 300-400 [mu]m particles, and has an absorption capacity elasticity index represented by formula (I) of 68,000 or more. Absorption capacity elasticity index = storage elastic modulus [Pa] centrifugal retention rate [g/g] ...(I).本發明提供一種吸水性樹脂及吸收性物品，該吸水性樹脂的吸水性能優異，且在使用於吸收體時，能夠使在荷重下的吸收性能提升，該吸收性物品使用了包含有該吸水性樹脂之吸收體。本發明的吸水性樹脂，其是藉由在內部交聯劑的存在下使水溶性乙烯性不飽和單體進行聚合，並且利用後交聯劑進行後交聯來獲得，其中，該吸水性樹脂在4.14kPa荷重下的生理食鹽水吸水能力是16mL/g以上，並且150~850μm的粒子佔該吸水性樹脂整體的質量比例是85質量%以上，進一步300~400μm的粒子的質量比例是20質量%以上，以下述公式(I)來表示的吸收容量彈性指數是68000以上，吸收容量彈性指數=儲存模數[Pa]×離心保持率[g/g]…(I)。
