A method of producing a particulate water absorbent resin, the method comprising: polymerizing an aqueous solution of an unsaturated monomer comprising acrylic acid and/ or a salt thereof as a main component and an internal cross-linking agent, and having a monomer concentration of 30% to 70% by weight to form a polymer gel, cracking the polymer gel in a gel grain refining step during polymerization or after polymerization to form a particulate water-containing gel-like cross-linked polymer, drying the particulate water-containing gel-like cross-linked polymer having a solids concentration of 30% by weight or greater to obtain a dried product, pulverizing the dried product to obtain a pulverization product and classifying the pulverization product obtained in the pulverizing step to obtain a water absorbent resin, using one or more apparatuses for aerating to provide aeration to the drying step for drying the particulate water-containing gel-like cross-linked polymer to the dried product, and/or to at least one of the pulverization step for pulverizing the dried product to the pulverization product, the classification step for classifying the pulverization product obtained after pulverization to obtain the water absorbent resin, or to a surface crosslinking step where present for crosslinking the surface of the water absorbent resin powder, thereby aerating any one of the particulate water-containing gel-like cross-linked polymer, the dried product, the pulverization product, or the classification product thereof; wherein the one or more apparatuses for aerating use a gas stream to provide aeration, and wherein the gas stream has a temperature in the range 100 to 250°C and a flowrate of 0.1 to 5 [m/s] at the place of aeration in the drying step and/or in at least one of the subsequent steps, wherein the gas stream used for aerating the water absorbent resin is reused after being reheated, and the passage of the gas stream through a filter occurs before the reheating of the gas stream, and wherein in the aerating apparatus, the gas stream used for aeration is passed through a filter with an area of opening per hole in the range 0.01 mm 2 to 500 mm 2 and then a portion or all of the gas stream is reused in the same step as the step where the aerating apparatus is installed, or in a different step, and wherein the method optionally further comprises the step of surface crosslinking the water absorbent resin obtained in the classification step to provide a part having a higher crosslinking density in the surface layer of the water absorbent resin. polymerizing an aqueous solution of an unsaturated monomer comprising acrylic acid and/ or a salt thereof as a main component and an internal cross-linking agent, and having a monomer concentration of 30% to 70% by weight to form a polymer gel, cracking the polymer gel in a gel grain refining step during polymerization or after polymerization to form a particulate water-containing gel-like cross-linked polymer, drying the particulate water-containing gel-like cross-linked polymer having a solids concentration of 30% by weight or greater to obtain a dried product, pulverizing the dried product to obtain a pulverization product and classifying the pulverization product obtained in the pulverizing step to obtain a water absorbent resin, using one or more apparatuses for aerating to provide aeration to the drying step for drying the particulate water-containing gel-like cross-linked polymer to the dried product, and/or to at least one of the pulverization step for pulverizing the dried product to the pulverization product, the classification step for classifying the pulverization product obtained after pulverization to obtain the water absorbent resin, or to a surface crosslinking step where present for crosslinking the surface of the water absorbent resin powder, thereby aerating any one of the particulate water-containing gel-like cross-linked polymer, the dried product, the pulverization product, or the classification product thereof; wherein the one or more apparatuses for aerating use a gas stream to provide aeration, and wherein the gas stream has a temperature in the range 100 to 250°C and a flowrate of 0.1 to 5 [m/s] at the place of aeration in the drying step and/or in at least one of the subsequent steps, wherein the gas stream used for aerating the water absorbent resin is reused after being reheated, and the passage of the gas stream through a filter occurs before the reheating of the gas stream, and wherein in the aerating apparatus, the gas stream used for aeration is passed through a filter with an area of opening per hole in the range 0.01 mm 2 to 500 mm 2 and then a portion or all of the gas stream is reused in the same step as the step where the aerating apparatus is installed, or in a different step, and wherein the method optionally further comprises the step of surface crosslinking the water absorbent resin obtained in the classification step to provide a part having a higher crosslinking density in the surface layer of the water absorbent resin.