Vehicle seat with securing means for a support element

The seat has a middle segment including a seat part (2') that is stowable under a seat part of a segment in a stowing position. The middle segment is connected with the segment in an operational position. The middle segment has a supporting element (13) by which the middle segment contacts with another segment in the operational position. The supporting element is secured in the operational position with respect to movement of the supporting element in a Z-direction and a Y-direction using a securing unit.