The present invention is a composition containing a polyester resin containing at least an alicyclic dicarboxylic acid component and an alicyclic diol component, and it is a polyester resin composition which satisfies that a glass transition temperature is 65° C. or more and 90° C. or less, a refractive index at sodium D line is 1.500 or more and 1.570 or less, a titanium element content is 5 ppm or more and 500 ppm or less, a phosphorus element content is 50 ppm or more and 500 ppm or less and a gel fraction is 50% or less. By the present invention, it is possible to obtain a polyester resin composition having a low refractive index and photoelastic coefficient, and in which a thermally degraded foreign substance is reduced.