An object is to improve both slow crystallization and brittleness that are drawbacks of polyhydroxyalkanoates, so that processability in mold processing, such as injection molding, is improved, processing speed is increased, and ductility is imparted to a resulting molded article. Provided is an aliphatic polyester resin composition including a polyhydroxyalkanoate (A), an ethylene-vinyl acetate copolymer resin (B), and pentaerythritol (C), wherein the ethylene-vinyl acetate copolymer resin (B) has a vinyl acetate content of 65 to 95 wt %, and the polyhydroxyalkanoate (A) and the ethylene-vinyl acetate copolymer resin (B) are compatible.