An automated 3D cup planning method in total hip arthroplasty from a standard X-ray radiograph is described. To achieve this objective, we integrate a statistical reconstruction method of 2D-3D pelvis shape reconstruction method and a 3D automated cup planning method which have been previously proposed. In performance evaluation, we virtually simulated scale estimation error in 2D-3D reconstruction. There were no significant difference both in cup size error and positional error between 2D-3D reconstruction based automated planning and 3D-CT based automated planning when a scale estimation errors were equal and less than ±5%. As future direction, we will study whether scale estimation accuracy less than ±5% can be achieved or not in real clinical application.