PURPOSE: To obtain a water-based coating compsn. without hazard and residual odor in the coating process and with high hardness and high gloss of coating film by compounding a water-soluble solvent, acidic aminoalkylated vinyl interpolymer, water and an epoxy resin.

CONSTITUTION: A water-based coating compsn. for woodworking consists of a water-soluble solvent, an acidic aminoalkylated vinyl interpolymer dissolved in this solvent [this interpolymer is an interpolymer with an aminoalkyl in the side chain of the formula (wherein R1 and R2 are each H or a 1-4C lower alkyl; (n) is 1.0-2.5 on average) and the interpolymer before aminoalkylation has at least 3wt.% side chain COOH and, in addition, the aminoalkyl groups are reacted with a sufficient amt. of acids to provide solubility in water], water and an epoxy resin.