PURPOSE: To easily teach the attitude of a graphic by calculating the angle between a calculate attitude direction and a specific reference direction of a tool coordinate system and correcting track data on the basis of the calculated angle and track.

CONSTITUTION: The tip 7a of a tool 7 is moved in the attitude direction of a graphic to be plotted by driving respective arm axes 1-6 of the robot 10 or two axes of the tool 7. Two points on the path where the tool tip 7a moves are extracted and the attitude direction of the graphic to be plotted is calculated on the basis of the coordinate positions of the tool tip 7a at the two points. The angle between the calculated attitude direction and the specific reference direction of the tool 7 on the coordinate system is calculated and the track data are corrected on the basis of the calculated angle and track data. Consequently, teaching regarding the attitude of the graphic can easily be ended.