[PROBLEMS] Disclosed is an aliphatic polyester copolymer which is excellent in heat resistance while having practically adequate mechanical properties and melting properties. [MEANS FOR SOLVING PROBLEMS] Specifically disclosed is an aliphatic polyester copolymer containing an aliphatic polycarbonate unit (a) and an aliphatic polyester unit (b). Also disclosed is a molded body composed of such an aliphatic polyester copolymer.
