The joint socket of a hip endoprosthesis consists of a socket shell (18) implantable in the pelvic bone (10) and a socket insert (20) for providing a bearing for the joint head (16). The socket shell (18) has an accommodating space having a conical inner surface in which the spherical outer surface of the socket insert (20) is inserted. As a result, the socket insert (20) can be clamped in self-retaining manner in any desired position of rotation and tilt in the accommodating space of the socket shell.