To provide an aliphatic or alicyclic polyester-based resin composition showing excellence in a balance of stiffness and mechanical strengths, weatherability and hydrolysis resistance.

The aliphatic or alicyclic polyester-based resin composition contains 100 pts.wt. of the aliphatic or alicyclic polyester-based resin (A), 0.001 to 2 pts.wt. of a hindered amine-based light stabilizer having two or more hindered amine structures (B), 0.01 to 10 pts.wt. of a carbodiimide-based compound (D), 1 to 50 pts.wt. of a filler (E), and preferably 0.001 to 2 pts.wt. of an ultraviolet absorber (C).