Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an artificial menstrual blood volume increase rate as measured in an artificial menstrual blood swelling test conducted in the order of i), ii), and iii) is 70% or more. i) putting 1.0 g of water-absorbent resin particles into a measuring cylinder with an inner diameter of 27 mm. ii) injecting 10 ml of artificial menstrual blood into the cylinder at once to swell the water-absorbent resin particles. iii) measuring a volume (A) of the swollen water-absorbent resin particles after 60 seconds from the injection and calculating an artificial menstrual blood volume increase rate according to Equation (I) below. Artificial menstrual blood volume increase rate (%)=(A−B)/B×100 . . . (I), A . . . Volume (ml) of swollen water-absorbent resin particles, B . . . Volume (ml) of injected artificial menstrual blood.