A sealing tool for a packaging machine comprises a sealing tool outer part, a sealing tool inner part that is movable in the sealing tool outer part, and a seal provided between the sealing tool outer part and the sealing tool inner part. The has a planar and annular design and is fixed in a first holding region at the sealing tool outer part as well as in a second holding region at the sealing tool inner part. The second holding region is disposed at or in the proximity of an outer edge of the sealing tool inner part.