To provide an absorber that has a high absorption speed, is unlikely to cause a liquid to remain on a skin-contacting surface, has excellent dry feeling, and is unlikely to cause excreted body fluid to return, and a water-absorbent resin powder that can be suitably used in the absorber. A water-absorbent resin powder of the present invention is characterized by meeting the following requirements (a) to (d): (a) a bulk density: 0.45 g/ml to 0.62 g/ml; (b) an absorption speed by a vortex method: 20 seconds to 50 seconds; (c) a liquid-passing speed under load: 10 seconds or less; and (d) a moisture absorption blocking ratio: 5% or less. An absorber of the present invention uses the water-absorbent resin powder of the present invention. An absorbent article of the present invention includes the absorber of the present invention.