The plug-in connector has an engagement verification mechanism using an elastically deflected locking arm (4) attached to the outer wall (1a) of the housing (1) of one connector half, engaged by a locking element (7) provided by the housing (2) of the second connector half. The locking arm has an attached engagement verification indictor (3), which is deflected when the connector halves are fully coupled and the locking arm is engaged by the locking element.
