The acetabulum (1) in accordance with the invention comprises a spherically formed outer shell (3) as well as a spherically formed inner shell (4) which is inserted into the outer shell (3). The inner shell (4) can, for example, consist of an oxide-ceramic material, in particular of aluminum oxide. The outer shell (4) can consist of, for example, titanium. The outer surface (4c) of the inner shell (4) is formed such that it has a first partial surface (4c) with increasing outer cross-section from the pole (2a) towards the equatorial opening (4b) to a site (4a) with a largest outer diameter, that a further partial surface (4e) with an outer cross-section decreasing towards the equatorial opening (4b) connects to the partial surface (4c), which goes into a further partial surface (4f) with increasing outer cross-section towards the equatorial opening. The outer shell (3) was plastically deformed at least in the region of the partial surface (4e), so that an operative connection results between the outer shell (3) and the inner shell (4) at least over the partial surface (4e).