PURPOSE: To obtain a composite excellent in water absorptivity, handleability, etc., expensively, by applying an aqueous solution containing a (meth)acrylate salt, a crosslinking monomer having a plurality of double bonds and a radical polymerization initiator to a molded fibrous base and polymerizing the monomers.

CONSTITUTION: An aqueous solution containing an alkali metal or ammonium salt of (meth)acrylic acid (A), a crosslinking monomer (B) having at least two double bonds in the molecule and being copolymerizable therewith (e.g., ethylene glycol diacrylate or diallyl phthalate) and a radical polymerization initiator (C) (e.g., t-butyl hydroperoxide) is prepared. This aqueous solution is applied to a molded fibrous base (e.g., paper or cotton gauze) and the component A is polymerized to form a highly water-absorptive polymer. In this way, the purpose water-absorptive composite is obtained. This composite can be suitably used for a variety of sanitary materials, soil conditioners, etc.