The present invention discloses a water-absorbent resin particle having a water absorption speed of 1 to 15 seconds for physiological salt solution, a median particle diameter of 100 to 600 μm, and a residual volatile component in an amount of 1.5wt% or less.本發明揭示一種吸水性樹脂粒子,其生理鹽水的吸水速度為1秒~15秒,中位粒徑為100μm~600μm,殘存揮發成分量為1.5質量%以下。