The invention relates to a device for connecting a connection pipeline to a rehabilitated pipeline which comprises a old pipeline (10) located radially outside and a renovating pipe (11) which is made of plastic and is drawn in the old pipeline (10). In order to achieve said connection, at least one flange (12) of steel, which is connected at the end face to the old pipeline (10), and at least one weld fitting (13) are provided, which can be welded outside with its inner side on an end region of the renovating pipe (11). According to the invention, the renovating pipe (11) is a plastic pipe which is drawn in the old pipeline (10) following a reduction of its outer diameter by means of a die and which has in the region of its projection (11b), which protrudes axially from the old pipeline, a shoulder (11a) to the outside in diameter, in comparison to the diameter of the renovating pipe within the old pipeline, and a plastic weld fitting (13), which is positioned axially before the old pipeline (10) over its en
