A water absorbing agent comprising water absorbent resin particles having a particle size of 1000 .mu.m or less, with a two-peak mode particle size distribution, which has an inflection point in the range of 750 to 250 .mu.m particle size prepared by plotting the mass cumulative content percentage from the larger side of the particle size of the particle size distribution on a logarithmic normal probability paper; and an absorbent material utilizing the water absorbing agent. Since the water absorbing agent of the present invention applied in an absorbent material can realize excellent absorption rate of a liquid and planar diffusion, an absorbent material with an excellent surface dryness can be obtained even for a long time use or when the ratio of the water absorbent resin is high due to a thin shape of the product, without the risk of leakage. Accordingly, the water absorbing agent of the present invention can be preferably used in an absorbent material such as a disposable diaper.