In a coaxial plug-connector part with a cap nut arranged in a rotatable manner on an outer conductor of a coaxial line system and with a ball bearing between cap nut and outer conductor, the ball bearing cooperates with a bearing bush. The ball bearing and the bearing bush are held within the cap nut by a bearing cover screw-connected to the cap nut, and this enclosed structural group can be fitted, via a continuous internal borehole of the bearing bush, onto the outer conductor of the coaxial line system to be connected.