Provided are: a water absorbing resin which has an excellent water absorption performance and with which it is possible to improve absorption performance under a load when used in an absorbent body； and an absorbent article using an absorbent body that includes the water absorbing resin. This water absorbing resin obtained by polymerising a water soluble ethylenically unsaturated monomer in the presence of an internal crosslinking agent and by post crosslinking using a post crosslinking agent has a physiological saline absorption capacity of 16 mL/g or more under a load of 4.14 kPa has a mass ratio of 85 mass% or more of 150 850 µm particles that account for a proportion of the entire water absorbing resin moreover has a mass ratio of 20 mass% or more of 300 400 µm particles and has an absorption capacity elasticity index represented by formula (I) of 68 000 or more. Absorption capacity elasticity index = storage elastic modulus [Pa] × centrifugal retention rate [g/g]...(I)
