Method for the production of an insulating profile (10; 30), in particular for the production of window, door and facade elements, wherein the insulating profile (10; 30) comprises an insulating bar manufactured from a first polymer material which comprises a profile body as well as a first functional element (22; 32) that extend in the longitudinal direction of the insulating profile (10; 30), wherein the first functional element (22; 32) is connected in a contact region to the insulating bar by a material bond, wherein, in a first step, both the profile body and the first functional element (22; 32) are each manufactured and provided separately, characterized in that in a second step downstream thereof, the profile body and the first functional element (22; 32) are supplied in the longitudinal direction of the insulating bar that is to be formed to an ultrasonic welding device in which the profile body and the functional element (22; 32) are connected to one another by a material bond by the formation of a welded joining, wherein the ultrasonic welding device comprises a welding zone that is equipped with a sonotrode , wherein the sonotrode has a recess in which the functional element (22; 32) is guided during the formation of the welded joining, and in that , during the formation of the welded joining, the profile body and the functional element (22; 32) are brought together into a predetermined first cross-sectional geometry as seen perpendicularly to the longitudinal direction and thereafter are guided with the predetermined first cross-sectional geometry or, if applicable, with a predetermined second cross-sectional geometry that differs from the first cross-sectional geometry, as seen perpendicularly to the longitudinal direction, until the plastics material of the welded joining has solidified to such an extent that the profile body and the first functional element (22; 32) are fixed with the predetermined cross-sectional geometry. wherein, in a first step, both the profile body and the first functional element (22; 32) are each manufactured and provided separately, characterized in that in a second step downstream thereof, the profile body and the first functional element (22; 32) are supplied in the longitudinal direction of the insulating bar that is to be formed to an ultrasonic welding device in which the profile body and the functional element (22; 32) are connected to one another by a material bond by the formation of a welded joining, wherein the ultrasonic welding device comprises a welding zone that is equipped with a sonotrode , wherein the sonotrode has a recess in which the functional element (22; 32) is guided during the formation of the welded joining, and in that , during the formation of the welded joining, the profile body and the functional element (22; 32) are brought together into a predetermined first cross-sectional geometry as seen perpendicularly to the longitudinal direction and thereafter are guided with the predetermined first cross-sectional geometry or, if applicable, with a predetermined second cross-sectional geometry that differs from the first cross-sectional geometry, as seen perpendicularly to the longitudinal direction, until the plastics material of the welded joining has solidified to such an extent that the profile body and the first functional element (22; 32) are fixed with the predetermined cross-sectional geometry. <EOS>