The invention relates to a luggage compartment separator (1) that changes the luggage compartment width in the vehicles with the component parts of two telescopic roof rails (2) that are positioned parallel to one another; four roof brackets (3) that enable said roof rails (2) to be mounted to the roof of the vehicle and are arranged at a quantity of two per roof rail (2); the top mat (4) that is positioned to separate the top-seat compartment of the vehicle and hangs down from said roof rail (2); the bottom mat (5) that is positioned adjacent to said top mat (4); at least one lock mechanism 1 (6) on said top mat (4) for enabling the top mat (4) to be secured to the side surface of the vehicle; the lock mechanism 2 (7) on the bottom mat (5) for connecting the bottom mat (5) and the top mat (4) with each other in both open and closed positions and for enabling the same to remain stationary; and the fixing mechanism (8) that enables the bottom mat (5) to be secured to the vehicle floor when in open position.