High-frequency plug device and plug connection system

The invention relates to a high-frequency plug-in device (01) for detachably contacting a coaxial contact partner (16), comprising an outer conductor assembly (02), which forms an end-side outer contact section (12), and an inner conductor assembly (03), which forms an end-side inner contact section (19), the outer conductor assembly (02) and the inner conductor assembly (03) are preferably jointly moved in the axial direction (A) relative to the guide sleeve (04) and can be shifted from a rest position into a contact position and back into the rest position, preferably under elastic deformation of the spring element (05), the outer conductor assembly (02) comprising an expansion body (11) arranged on the end side, the expansion body (11) is designed in such a way that, when the contact position is reached, a force acting on the expansion body (11) by the contact partner (16) in the axial direction (A) causes a radial deformation of the expansion body (11), which presses the outer contact portion (12) from th