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