A device for treating obesity including a band part (1), which can be applied in a ring shape around the stomach, the band part (1) having a closure mechanism (2, 3) with which the band part (1) can be closed to form a circumferentially closed ring having an opening (4) with a central axis (5), and a support part (17), which is connected to the band part (1) and which protrudes from the latter on one side and provides support for a stomach area lying proximally with respect to the applied band part (1). The support part (17) extends by less than 270° about the central axis (5) in the sectional plane of each cross section that passes through the support part (17) and lies parallel to a mid-plane (6) in which the band part (1) closed to form a ring lies and which extends centrally through the band part.
