PURPOSE: To improve the water absorptivity and strength at swell of the resulting water absorbent, by partially or completely neutralizing a graft copolymer obtained by grafting a specified amount of a water-soluble unsaturated carboxylic acid onto PVA.

CONSTITUTION: PVA is dissolved in hot water, and onto the PVA is grafted a water-soluble unsaturated carboxylic acid such as acrylic acid, methacrylic acid or maleic acid by using a graft polymerization initiator and, if necessary, a crosslinking agent. Next, the resulting graft copolymer is partially or completely neutralized with an alkali metal hydroxide so that the PVA portion constitutes 1W50wt% of the graft copolymer. After the neutralization the polymer is washed with an alcohol to remove the initiator and the remaining monomer. The water absorbent thus produced has a high strength at swell and therefore destruction of the gel structure when swollen does not occur even when the absorbent is long kept in the water- swollen state.