A device for arranging a passenger restraint system in a vehicle to secure a passenger seated in the vehicle, including a support arrangement having a vertical support and a cross strut. When arranged on the vehicle, the vertical support is arranged upright on a vehicle floor. The device includes a fastening element, that when arranged on the vehicle, encompasses a rail of a vehicle chassis, at least laterally and beneath, such that, when the support arrangement is arranged on the vehicle, the fastening element bears against the support arrangement. The support arrangement is held on the vehicle chassis by the fastening element and, when the support arrangement is arranged on the vehicle, the fastening element passes progressively through the vehicle floor, starting from the rail of the vehicle chassis.