Automatic welding system for pipeline

The present invention relates to an automatic welding system for a pipeline, in which an automatic welding head having a plurality of wheels is attached to the pipeline, and when the wheels are driven by a chain to rotate along with the circumferential surface of the pipeline, welding is easily performed by a welding device. In the present invention, an automatic welding head (2) is rotatably attached to a pipe (1) and welded by a welding machine (15), a chain (3) is wound around the pipe (1), the automatic welding head (2) is rotatably provided along the chain (3), and the chain (3) is movably passed through through openings (6a) formed on both sides of the automatic welding head (2). When a chain (3) is wound around a gear driven to rotate by a drive motor (9) provided on an automatic welding head (2), a wheel (4) provided on the automatic welding head (2) is guided by a guide roller (11), and rotates along with the pipe (1), the pipe (1) is precisely welded by a welding machine (15) whose position is adjus