PURPOSE: To provide a flash removing robot which can grind in a short time without generating a part not ground or ground too much.

CONSTITUTION: The shape of a flash 4a formed in front of a grinder 8 in the moving direction is detected by a visual sensor device 3. The optimum pressing force and moving speed of the grinder 8 corresponding to the detected shape of the flash 4a are set. The grinder 8 grinds based on the pressing force and the moving speed. Moreover, the shape of a rear ridge of a work 4 in the moving direction of the device 3 is detected by the visual sensor device 3. Accordingly, whether the flash 4a is completely ground is detected. In the case where the flash 4a is perfectly ground, this path is completed. If the flash 4a is not ground perfectly, this path is repeated again.