PROBLEM TO BE SOLVED: To provide absorbent resin particles capable of preventing expansion after water has entered a disposable swimsuit and preventing urine leakage before entering water, and an absorbent article using the same. An absorbent resin particle obtained by cross-linking resin particles containing a cross-linked polymer (A) containing a vinyl monomer (a) and a cross-linking agent (b) as essential constituent units with a post-cross-linking agent (c), Absorbent resin particles having a [water absorption capacity in ion-exchanged water] of 10 to 120 (g / g) and a [gel passage rate of the absorbent resin particles] of 350 (ml / min) or more. [Selection diagram] None【課題】使い捨て水着内に水が入った後の膨張を防止しつつ、かつ水に入る前における尿漏れを防止可能な吸収性樹脂粒子及びこれを使用した吸収性物品の提供。【解決手段】ビニルモノマー（ａ）及び架橋剤（ｂ）を必須構成単位とする架橋重合体（Ａ）を含有する樹脂粒子を後架橋剤（ｃ）で架橋した吸収性樹脂粒子であって、［イオン交換水中での吸水倍率］が１０～１２０（ｇ／ｇ）であり、［吸収性樹脂粒子のゲル通液速度］が３５０（ｍｌ／分）以上である吸収性樹脂粒子。【選択図】なし
