Water absorbent resin powder comprising a polyacrylic acid (salt)-based water absorbent resin as a main component, the water absorbent resin powder satisfying the following conditions (A) to (C): (A) the water absorbent resin powder containing particles smaller than 150 µm in a ratio of 0 mass% to 4.5 mass% before an impact resistance test, and the water absorbent resin powder containing, in a ratio of 0 mass% to 4.5 mass%, particles smaller than 150 µm and increased by the impact resistance test； (B) the water absorbent resin powder having an absorption capacity under load (AAP) of not less than 17； and (C) the water absorbent resin powder having a thermal conductivity of not more than 125 [mW/(m·K)].
