A teaching system includes an image generating unit, a projecting unit, a work line generating unit, an arithmetic unit, and a job generating unit. The image generating unit generates a virtual image including a robot and a workpiece having a processed surface to be processed by the robot. The projecting unit generates a projection plane orthogonal to a normal direction of a desired point on the processed surface selected on the virtual image and projects the processed surface onto the projection plane. The work line generating unit generates a work line for the robot based on setting contents received via the projection plane. The arithmetic unit calculates a teaching value including the position and the posture of the robot at each point of the target points. The job generating unit generates a job program for operating the robot in an actual configuration based on the teaching value.