Disclosed are a copolymeric polyester resin composition having outstanding color stability (transparency) and a production method therefor. The copolymeric polyester resin composition comprises: between 95 and 99.99 percent by weight of a copolymeric polyester resin having a structure which is obtained by the copolymerization of a dicarboxylic acid component and a diol component that comprises isosorbide, and in which there is repetition of a dicarboxylic acid moiety derived from the dicarboxylic acid component and a diol moiety derived from the diol component; and between 0.01 and 5 percent by weight of an antioxidant selected from the group consisting of hindered phenol-based antioxidants, phosphite-based antioxidants, thioether-based antioxidants and mixtures thereof.