Abstract: A plug connector has a male plug part, connected to an electric connecting cable and having contact elements, and a female plug part with matching counter contact elements providing electric contact in a contact position established when the male plug part is inserted into the female plug part. The female plug part has a sleeve-shaped housing having an inner circumferential surface with a locking edge. The male plug part has a locking sleeve and an outer sleeve axially slipped onto the locking sleeve. The outer sleeve has locking tabs engaging the locking edge in the contact position. The locking sleeve has several tongue-shaped thickened portions distributed circumferentially that have radially outwardly positioned cone-shaped locking surfaces. The locking tabs are spaced circumferentially from one another by a spacing that allows the thickened portions to pass between the locking tabs when the outer sleeve is slipped onto the locking sleeve.