To provide a polyester carbonate type copolymer resin being excellent in transparency, solvent solubility, and, especially, abrasion resistance and being easily handleable and to provide a coating film made from the same.

Provided are a copolymer resin which is a copolymer of 99.9-90 wt.% polyester carbonate (D) which comprises 5-70 wt.% aromatic polyester part (A) constituted from an aromatic dicarboxylic acid component and an aromatic diol component, 10-75 wt.% polyester part (B) constituted from an aromatic dicarboxylic acid component or an aliphatic dicarboxylic acid component and aliphatic diol residues, and 20-85 wt.% aromatic polycarbonate part (C), in which these parts are chemically bonded to each other, and which is terminated with a double bond with 0.1-10 wt.% monomer (E) having a double bond copolymerizable therewith and has a number-average molecular weight (Mn) of 10,000-700,000 and a coating film made from the copolymer resin and having a transmittance of at least 85% to light in a wavelength region of 400-800 nm (as measured on a coating film having a thickness of 25 μm).