Provided is a method for manufacturing a water absorption treatment material, according to which it is possible to suppress a decrease in water-absorptivity caused by the existence of a coating portion. A manufacturing method according to an embodiment of the present invention includes a core portion forming step, a coating portion forming step, and a core portion removing step. The core portion forming step is a step of forming a core portion (10) in a granular shape. The coating portion forming step is a step of forming a coating portion (20) so as to cover the core portion (10). The coating portion removing step is a step of removing a part of the coating portion (20).
