PURPOSE: To obtain a water-absorptive composite material having excellent water absorptivity and an arbitrary shape, by impregnating a water-absorptive organic material with an aqueous solution of a polymerizable monomer based on acrylic acid (salt), polymerizing this monomer and drying the product.

CONSTITUTION: An aqueous solution of a polymerizable monomer based on acrylic acid and/or an acrylate is infiltrated into a water-absorptive organic material such as paper, nonwoven fabric, or foamed plastic, and polymerized. The product is dried to produce a water-absorptive composite material. According to this process, a water-absorptive material of an arbitrary shape can be obtained in one step because the shape of the water-absorptive organic material is the same as that of the final product. Because a water-absorptive composite material suitable for a condition of use can be produced, the scope of its use can be widened. Examples of the acrylates include those of ammonium, sodium, potassium and lithium.