The water absorbent material of the present invention is composed of a copolymer
of an anhydropolyamino acid having at least one ethylenically unsaturated double
bond in a molecule, a water-soluble monomer having an ethylenically unsaturated
double bond and polysaccharides, and has high water absorption ratio and high water
absorption rate in pure water or water having a low ion content and also has high
absorption properties for high concentration salt-containing solutions.