Abstract: An automatic vehicle body sanding system operated in a painting factory includes a painting inspection device configured to detect a defective position (NG Point) by analyzing a 2D image of a vehicle body for which an intermediate process has been completed taken with a camera, and display the defective position on a 3D vehicle body drawing. The automatic vehicle body sanding system includes a robot having a multi-joint structure on which at least one of a 3D scanner, a sanding tool, and a dust absorber required for sanding work is mounted. Further, the automatic vehicle body sanding system includes a server configured to match the defective position of the vehicle body detected by the painting inspection device and 3D scan data of the vehicle body scanned by the 3D scanner with a 3D vehicle body drawing shape on a simulator.