Provided is an automatic teaching system that is readily able to achieve automation, even when a small but varied number of processing objects are to undergo polishing or coating. The automatic teaching system includes a three-dimensional shape measurement apparatus, a reference marker, an image analysis apparatus, and a robot control device. The three-dimensional shape measurement apparatus acquires shape data of a processing target region on a processing object relative to the reference marker, and the image analysis apparatus divides the shape data of the processing target region into a plurality of continuous reference surfaces, in accordance with a predetermined algorithm, automatically generates a program of an operation path along which a polishing apparatus or coating apparatus of the robot is to be operated, for every reference surface, in accordance with a predetermined operation path generation rule, and transmits the program of the operation path to the robot control device.