New concept of sliding door, so called Invisible Rail Sliding Door (IRSD), for sedan or small RV vehicle is proposed. Sliding rail for IRSD is located inside of vehicle, unlike usual sliding door that has the rail located outside of vehicle. So, Sliding rail of IRSD is not shown from outside view, and that might increase the feeling of exterior design. In this study, we considered a new 6-bar linkage mechanism for AM Rr door and verified the usefulness by CAE and examination.