A fixing device for fixing a swap body in or on the pick-up area of a vehicle. At least one support structure is positioned in the pick-up area, with at least one pick-up floor positioned in the pick-up area, with at least one rail-style guide element spaced from the pick-up floor which is fixed to the support structure or the swap body and which demonstrates a guide surface. At least one support element is positioned on a swap body or on the support structure which is positioned between the guide element and pick-up floor when transferring the swap body into the pick-up area or out of the pick-up area. At least the guide surface of at least one guide element demonstrates an incline in relation to the pick-up floor.