Window rebate ventilator (1, 1a), comprising a ventilator housing (2, 2a) for fastening on the interior side to the fixed frame of a window or a door above or below a window or door cover and/or for fastening in a window rebate formed between the fixed frame and the sash frame of a window or a door, wherein the ventilator housing (2, 2a) comprises at least one ventilator housing chamber (9a, 9b) which has a front side, which forms a stop side of the ventilator housing (9a, 9b) to be fastened to fit against the fixed frame, as well as a bottom wall having at least one, in particular slot-shaped, bottom opening, a top wall formed opposite and spaced apart from the bottom wall, a rear wall connecting the bottom wall and the top wall to one another, as well as two side walls arranged opposite one another and each connecting the bottom wall, the rear wall and the top wall to one another, and wherein the top wall has at least one, in particular slot-shaped, top opening and the rear wall and the side walls are configured to be closed, and wherein the at least one bottom opening and the at least one top opening are part of an air flow path which runs through the interior of the at least one ventilator housing chamber (9a, 9b) of the ventilator housing (2, 2a), and wherein in the interior of the at least one ventilator housing chamber (9a, 9b) at least one volume flow limiter is mounted suspended in the air flow path so as to be pivotally movable in such a way that the volume flow limiter regulates an air volume flow flowing between the at least one bottom opening and the at least one top opening along the air flow path through the interior of the at least one ventilator housing chamber (9a, 9b) by means of its pivoted positions varying automatically in dependence on the air pressure between an open position permitting the greatest possible air volume flow and a closed position limiting, preferably completely preventing, the air volume flow, wherein the air volume flow limiter comprises a flap, which in the closed position abuts against a stop element on the closure side, and a counterweight element, preferably angularly, attached thereto and projecting therefrom, characterized in that the at least one bottom opening and the at least one top opening in the front side region of the ventilator housing chamber (9a, 9b) are formed directly adjoining the stop side of the ventilator housing (2, 2a) or adjacent to the stop side of the ventilator housing (2, 2a) with a small distance therebetween, and the at least one volume flow limiter is mounted in a region of the ventilator housing chamber (9a, 9b) opposite thereto at a distance adjacent to the rear wall and preferably at a small distance from the top wall on its laterally opposite sides (61a, 61b) in each case in a side wall or a bearing element arranged parallel thereto so as to be pivotally movable in a suspended manner, and in that the top wall forms the closure-side stop element, the flap being configured, on the one hand, to be heavier than the counterweight element and, on the other hand, being dimensioned in such a way that, pivoted into its closure position, it abuts against the inner side of the top wall, covering, depending on the number, at least one or more top openings of an air guiding chamber (9a, 9b) and closing, at least approximately, the air flow path. the at least one bottom opening and the at least one top opening in the front side region of the ventilator housing chamber (9a, 9b) are formed directly adjoining the stop side of the ventilator housing (2, 2a) or adjacent to the stop side of the ventilator housing (2, 2a) with a small distance therebetween, and the at least one volume flow limiter is mounted in a region of the ventilator housing chamber (9a, 9b) opposite thereto at a distance adjacent to the rear wall and preferably at a small distance from the top wall on its laterally opposite sides (61a, 61b) in each case in a side wall or a bearing element arranged parallel thereto so as to be pivotally movable in a suspended manner, and in that the top wall forms the closure-side stop element, the flap being configured, on the one hand, to be heavier than the counterweight element and, on the other hand, being dimensioned in such a way that, pivoted into its closure position, it abuts against the inner side of the top wall, covering, depending on the number, at least one or more top openings of an air guiding chamber (9a, 9b) and closing, at least approximately, the air flow path.