To provide a polyester resin composition excellent in moldability, flexible and exhibiting excellent heat resistance, chemical resistance and the like and to provide a molded article thereof.

The title polyester resin composition comprises (I) a polyester- based elastomer comprising a polyester containing as a constituting unit a silicone compound, (II) a polymethylol type alkyl phenol compound and (III) a crosslinking agent. The polyester is caused to contain 5-30 wt.% of the silicone compound as a constituting unit, and as the crosslinking agent (III) can be employed an epoxy compound having 3 or more functionalities. Blow moldings are composed of a polyester resin composition comprising 100 pts.wt. of the polyester resin composition having incorporated therewith 0.05-5.0 pts.wt. of a pigment.