PURPOSE: To obtain the subject composition having excellent thermal stability in retention, impact resistance and fluidity by blending an aromatic polycarbonate resin with a saturated polyester resin and a specific modified olefin copolymer.

CONSTITUTION: 100 pts.wt. mixture of (A) 10-90wt.% aromatic polycarbonate resin (preferably one comprising bisphenol A as a main raw material) and (B) 90-10wt.% saturated polyester resin (preferably polybutylene terephthalate) are mixed with (C) 2-40 pts.wt. modified olefin copolymer prepared by polymerizing 10-400 pts.wt. ester-based monomer selected from an alkyl (meth)acrylate and an alkyl vinyl ester [preferably methyl (meth)acrylate or vinyl acetatel] in the presence of 100 pts.wt. crystalline polyolefin polymer (preferably polyethylene) to give the objective composition. The composition is preferably obtained by blending the components A to C simultaneously and granulating by an extruder.