The present invention provides a polyester resin composition excellent in transparency and flexibility, high in heat resistance, undergoes the bleeding-out of an oligomer at a reduced level, and can be formed into a formed or molded article or pellets that are rarely agglutinated. A polyester resin composition includes a polyester resin, made by a polymerization reaction of a dicarboxylic acid component containing (a) 75 to 98 mol% of an alicyclic dicarboxylic acid, preferably having 5 to 30 carbon atoms, and (b) 2 to 25 mol% of a dimer acid, preferably having 36 or 44 carbon atoms, with (c) a diol component containing 75 mol% or more of an alicyclic diol. The proportion of the trans-form relative to the total amount of the trans-form and the cis-form of the alicyclic dicarboxylic acid unit contained in the polyester resin composition is desirably 80% or more.