Water-absorbing resin particles, absorbent, and absorbent article

Water-absorbent resin particles comprising:

• a crosslinking polymer comprising a structural unit derived from an ethylenically unsaturated monomer,
• wherein the ethylenically unsaturated monomer comprises at least one compound selected from the group consisting of (meth)acrylic acid and a salt thereof,
• a ratio of the (meth)acrylic acid and the salt thereof is 70 to 100 mol % with respect to a total amount of monomers for obtaining the water-absorbent resin particles,
• a water retention amount of physiological saline is 30 to 80 g/g,
• a medium particle diameter is 250 to 850 μm, and
• a swelling height measured by the following procedures (1) to (6) is 10 mm or less,
• (1) a container having a recess having a bottom area of 50 cm2 is disposed in a state where the recess is open in a vertical direction,
• (2) 1.00 g of water-absorbent resin particles are disposed in the recess,
• (3) a non-woven fabric is disposed on the water-absorbent resin particles in the recess,
• (4) a weight having a mass of 90 g is disposed on the non-woven fabric,
• (5) physiological saline is supplied into the recess,
• (6) a movement distance in a vertical direction of the weight when 300 seconds have passed from the start of swelling of the water-absorbent resin particles is measured as the swelling height.