To obtain a polyvinyl alcohol(PVA)-based resin composition capable of providing sufficient water resistance even when dried at a relatively low temperature without causing discoloration or degradation and without releasing a substance adversely affecting human bodies after cross-linking, and a paper coating agent consisting essentially of the PVA-based resin composition.

This PVA-based resin composition is obtained by compounding (A) a cyclic carbonate group-containing PVA-based polymer containing 0.01-35 mol% of cyclic carbonate units represented by the formula in the side chain with (B) a hydrazine compound.