A water-absorbing agent comprising: a water-absorbing resin obtained by surface-crosslinking a water-absorbing resin powder which contains a polyacrylic acid-based water-absorbing resin and/or a polyacrylic acid salt-based water-absorbing resin as a main component and which has a BET specific surface area of not less than 0.027 m 2 /g, said water-absorbing agent satisfying to, and below: a saline flow conductivity is not less than 20×10 -7 cm 3 ·s·g -1; a gap fluid retention property under pressure is not less than 9 g/g; a proportion of particles having a particle diameter of not less than 150 μm and less than 710 μm is not less than 90 weight%, and a proportion of particles having a particle diameter of not less than 710 μm is not more than 5 weight%; a centrifuge retention capacity is not less than 25 g/g; a fluid retention capacity under pressure is not less than 20 g/g; a weight average particle diameter is 300 μm to 450 μm; and a logarithmic standard deviation (σζ) of a particle size distribution is 0.25 to 0.45, wherein, in, when a water-absorbing resin is swollen in a 0.69 weight% aqueous sodium chloride solution, said gap fluid retention property under pressure is a weight of the aqueous sodium chloride solution per gram of said water-absorbing agent, the sodium chloride solution being retained under a load of 2.07 kPa in gaps within said water-absorbing agent. a water-absorbing resin obtained by surface-crosslinking a water-absorbing resin powder which contains a polyacrylic acid-based water-absorbing resin and/or a polyacrylic acid salt-based water-absorbing resin as a main component and which has a BET specific surface area of not less than 0.027 m 2 /g, said water-absorbing agent satisfying to, and below: a saline flow conductivity is not less than 20×10 -7 cm 3 ·s·g -1; a gap fluid retention property under pressure is not less than 9 g/g; a proportion of particles having a particle diameter of not less than 150 μm and less than 710 μm is not less than 90 weight%, and a proportion of particles having a particle diameter of not less than 710 μm is not more than 5 weight%; a centrifuge retention capacity is not less than 25 g/g; a fluid retention capacity under pressure is not less than 20 g/g; a weight average particle diameter is 300 μm to 450 μm; and a logarithmic standard deviation (σζ) of a particle size distribution is 0.25 to 0.45, a saline flow conductivity is not less than 20×10 -7 cm 3 ·s·g -1; a gap fluid retention property under pressure is not less than 9 g/g; a proportion of particles having a particle diameter of not less than 150 μm and less than 710 μm is not less than 90 weight%, and a proportion of particles having a particle diameter of not less than 710 μm is not more than 5 weight%; a centrifuge retention capacity is not less than 25 g/g; a fluid retention capacity under pressure is not less than 20 g/g; a weight average particle diameter is 300 μm to 450 μm; and a logarithmic standard deviation (σζ) of a particle size distribution is 0.25 to 0.45, wherein, in, when a water-absorbing resin is swollen in a 0.69 weight% aqueous sodium chloride solution, said gap fluid retention property under pressure is a weight of the aqueous sodium chloride solution per gram of said water-absorbing agent, the sodium chloride solution being retained under a load of 2.07 kPa in gaps within said water-absorbing agent.