A plug connector for an electrical plug connection including a contact chamber housing, having a plurality of contact chambers for receiving a contact body each, which is introducible into the contact chamber and is primarily engaged in the contact chamber housing in its end position, and having a secondary locking element which is guided displaceably across the direction of introduction of the contact bodies and which, in its locking position, respectively protrudes laterally into the contact chambers with a locking projection for secondarily locking the contact bodies primarily engaged there. The contact chamber housing is subdivided into a plurality of contact chamber housing sections each having at least one series of contact chambers by one or more parallel separating gaps, each of the contact chambers being open toward a separating gap or an outside of the contact chamber housing parallel thereto, the secondary locking element is a frame subdivided into compartments by one or more parallel partitions, the partitions engaging into the separating gaps when the secondary locking element is plugged onto the contact chamber housing, closing the laterally open contact chambers, and the secondary locking element plugged onto the contact chamber housing is displaceably guided across the direction of introduction of the contact bodies into the locking position.