To provide a resin compsn. for a thermosetting paint capable of using in conventional painting method and thermosetting method, having a low viscosity and excellent in workability without using an org. solvent, capable of high solidification, and having environmental compatibility.

This compsn. contains as essential components a multifunctional (meth)acrylate (A) having at least 2 (meth)acryloyl groups in a molecule and a mol.wt., per (meth)acryloyl group, of 84-980, and a resin (B) comprising a polyester resin (B1) having at least a functional group contg. an active hydrogen in a molecule and a number average mol.wt. of 2,000-20,000 and/or an acrylic resin (B2).