PURPOSE: To obtain the titled UV-curable composition forming a coating film when applied to a floor surface and dried, keeping beautiful appearance of the floor, preventing staining of water and protecting the substrate, by using a specific thermoplastic polymer, a specific photo-polymerizable prepolymer and a photo-polymerization initiator as essential components.

CONSTITUTION: The objective UV-curable composition contains (A) at least one kind of thermoplastic polymer (preferably acrylic polymer or styrene polymer), (B) a photo-polymerizable prepolymer and (C) a photo-polymerization initiator. The polymer of the component A and/or the prepolymer of the component B contain carboxylic acid group and/or carboxylic acid salt group. The composition preferably further contains a solvent (preferably a photo- polymerizable monomer or water).