Abstract: An insert (3) is arranged in the interior space (10) of a housing (1) of an opening device for an open-end spinning apparatus. The insert (3) is of pot-like construction with a recess (35) provided in the base (34). The recess (35) exposes a bearing bore (18) through which a drive shaft extends for supporting the opening roller. A fixing device (41, 42) is likewise associated with the insert (3) securing its relative position to the housing. A guide element (5) introducible into the insert (3) is provided to guide the insert (3) during introduction into the housing (1) or during its removal. This has a contour corresponding to the interior space (10) of the housing (1) and one or more positioning lugs (50) on its end face opposite the base (34), corresponding to the number of the positioning cavities provided in the insert (3).