To provide a water-based synthetic resin composition hardly causing problems on the environmental hygiene, suitable for a coating material, ink, an adhesive, a coating agent or the like, and capable of being crosslinked at normal temperature.

The normal temperature-crosslinkable water-based synthetic resin-dispersed composition is obtained by adding a quaternized chitosan represented by general formula (1) (wherein, R is a lower alkyl group; X- is a halogen ion; and m and n are each a positive integer) as a crosslinking agent to an aqueous dispersion of a polymeric resin of a copolymer of a carbonyl group-containing unsaturated monomer and at least one kind of a monomer selected from unsaturated carboxylic acid compounds, and having (-20)-(+50)°C glass transition temperature.