Abstract: An auto-scraping apparatus for a work piece of a hard rail has a driving device, a linking device and a tool device. The driving device has a connecting frame, a driving motor and a cam. The driving motor is mounted in the connecting frame. The cam is mounted on a bottom of the connecting frame and has an abutting face. The linking device is connecting to the driving device and has a main frame, an upper connecting arm, a lower connecting arm, a linking arm and a rotating wheel. The main frame is connected to the driving motor. The connecting arms are pivotally connected to the main frame and the linking arm. The rotating wheel is rotatably mounted on the upper connecting arm and abuts the abutting face of the cam. The tool device is connected to the linking device and has a tool carrier and a relieving tool.