A circular plug-type connector for a multi-core electrical cable, which is provided in each case with male or female contacts, possesses an inner insulating body for holding the individual male or female contacts in its interior. This insulating body is provided with its cable-side end region in a sleeve-shaped holding ring in such a way that it can be plugged in. A top piece can be fastened rotatably on the holding ring. The top piece is formed with a thread for connection to a mating plug-type connector. A sleeve-shaped housing, which can be assembled from at least two housing parts, can be fastened with its one axial end on the cable-side end region of the holding ring. The cable can be inserted into the housing and fastened thereon with resistance to tensile stress at the other axial end of the housing. A coupling unit comprising two circular plug-type connectors, which can be fastened detachably to one another using screws, for a multi-core electrical cable that is provided in each case with male or female contacts is characterized in that one circular plug-type connector has plug-type contacts and the other plug-type connector has female contacts.