A coupling device, in particular a multiple coupling (1), connects a first line portion to a second line portion by a first coupling body (3) and second coupling body (5). A connection unit (23, 25) can be inserted into an accommodating opening (41, 42) in each coupling body (3, 5). A plug-in connection between line portions having electric conductors has an electrical connector (63) with plug-shaped and/or socket-shaped contact elements (67, 69). The connection unit (23, 25) is a cartridge with a single-part, sleeve-shaped housing (37) having a through-passage (39) accommodating the connector (63).