Abstract: The invention relates to a method and a device for heating an end section of a plastic pipe (1) to prepare for the formation of a sleeve on the plastic pipe, such that the end section can be heated to the deformation temperature of the plastic pipe or even higher by heating on the exterior by means of external heating jaws (2, 3) and on the interior by means of a heating mandrel (4) that can be inserted from the end into the plastic pipe (1).