The present invention relates to a polylactic acid resin composition useful as a packaging material which has not only improved flexibility but also superior external appearance and superior properties such as mechanical property, transparency, heat resistance, anti-blocking property, workability of a film, and the like, and a packaging film including the same.The polylactic acid resin composition comprises a polylactic acid resin including a hard segment comprising a polylactic acid repeating unit and a soft segment comprising a polyurethane polyol repeating unit in which polyether polyol repeating units are linearly linked via a urethane bond; and a specific content of antioxidant.