A device that is made up of some fixed guides (2) anchored to the inner floor (P) of the ambulance onto which a removable tray (3) is fitted and which can be withdrawn by said fixed guides (2) towards the outside of the ambulance for the reception of the stretcher (1), this tray (3) having some rails (34) on its upper part for the frontal introduction and for the support of the primary wheels (12) of a stretcher (1) in the horizontal position, when the stretcher (1) has a foldable base (13) completely unfolded, making the introduction and extraction of said tray assembly (3) with the stretcher (1) into the ambulance easier, after the folding of said foldable base (13), keeping the horizontal line of the stretcher (1) at all times.
