Welding seam information setting device, program, automatic teaching system and welding seam information setting method

The invention provides a welding seam information setting device, a program, an automatic teaching system and a welding seam information setting method. Through notifying matching state of information which comprises welding seam constituents of a new workpiece model to operation personnel, information correction and deleting of information can be performed, and furthermore high matching performance of the welding seam information of the new workpiece model is ensured. A welding seam information setting device sets the welding seam information of the workpiece for welding indication before operation of a welding robot, and is provided with the components of: a welding seam information storage part (61) which stores the welding seam information of a basic workpiece model; a similar workpiece structure information acquiring part (51) which acquires structure information of a similar workpiece model that has a different size from that of the basic workpiece model and a similar shape to that of the basic workpiec