A device and a method are for sealing a catheter part into a film sleeve. Molding plates are provided with molding indentations which have a one-dimensionally curved cross-sectional shape. In molding stations, base and cover film sections are placed without strain into the molding indentations. In an introduction station, at least one catheter part is introduced into a corresponding molding indentation. In a sealing station, the catheter part is sealed into a film sleeve by the base film section and the cover film section being sealed onto one another at common sealing sections and being sealed onto sealing faces of the catheter part while forming the film sleeve.