A connecting device for connecting a high-frequency (HF) cable, in particular a coaxial cable, to an HF interface, in particular a coaxial plug-in connector or hollow conductor, wherein the connecting device has a sleeve, which is formed at a first axial end for plugging with a connection part of the HF interface and at a second end axially opposite the first end for connecting to the HF cable, wherein a surface of the sleeve, which faces the connection part of the HF interface in the plugged state of the sleeve and the connection part of the HF interface, is provided with at least one first groove in the axial direction, wherein at least one cylindrical pin is provided for engaging in at least one first groove.