Magnetic plate separator for spacing the upper plates of a stack of steel plates in vertical direction, comprising: - a housing provided with an elongated work surface which, during operation, is present next to a stack of plates and is vertically oriented in longitudinal direction, as well as - a magnet assembly of at least two elongated permanent magnets (9, 11) which are movably present in the housing and are vertically oriented also in longitudinal direction during operation, and - displacement means for displacing the magnet assembly between an active state near the work surface and an inactive state remote from the work surface, characterized in that of the magnet assembly a first magnet is fixed to a first shaft and a second magnet to a second shaft, which shafts are rotatable in mutually opposite directions, where in the active state the first magnet is facing the work surface with the magnetic North Pole and the second magnet is facing the work surface with the magnetic South Pole and the other poles (9Z, 11N) of the magnets are interconnected via at least one magnetic conductor, and where in the inactive state the North Pole of the first magnet and the South Pole of the second magnet are facing each other and the other poles (9Z, 11N) of the magnets are magnetically connected to each other via the magnetic conductor, in that the magnetic conductor is arranged between the two permanent magnets (9, 11), in that the magnetic conductor is formed by a solid cylinder of magnetic material and, during operation, is also vertically oriented and has a cross-section that is provided with a first end face facing the work surface and a second end face turned away from the work face and sides extending between the first and second end faces and extending along a part of a circular arc, in that the second end face turned away from the work surface is larger than the first end face facing the work surface, and in that the centres of the circular arcs coincide or substantially coincide with the axes of the shafts (13, 15) on which the first and second permanent magnets (9, 11) are fixed. - a housing provided with an elongated work surface which, during operation, is present next to a stack of plates and is vertically oriented in longitudinal direction, as well as - a magnet assembly of at least two elongated permanent magnets (9, 11) which are movably present in the housing and are vertically oriented also in longitudinal direction during operation, and - displacement means for displacing the magnet assembly between an active state near the work surface and an inactive state remote from the work surface, characterized in that of the magnet assembly a first magnet is fixed to a first shaft and a second magnet to a second shaft, which shafts are rotatable in mutually opposite directions, where in the active state the first magnet is facing the work surface with the magnetic North Pole and the second magnet is facing the work surface with the magnetic South Pole and the other poles (9Z, 11N) of the magnets are interconnected via at least one magnetic conductor, and where in the inactive state the North Pole of the first magnet and the South Pole of the second magnet are facing each other and the other poles (9Z, 11N) of the magnets are magnetically connected to each other via the magnetic conductor, in that the magnetic conductor is arranged between the two permanent magnets (9, 11), in that the magnetic conductor is formed by a solid cylinder of magnetic material and, during operation, is also vertically oriented and has a cross-section that is provided with a first end face facing the work surface and a second end face turned away from the work face and sides extending between the first and second end faces and extending along a part of a circular arc, in that the second end face turned away from the work surface is larger than the first end face facing the work surface, and in that the centres of the circular arcs coincide or substantially coincide with the axes of the shafts (13, 15) on which the first and second permanent magnets (9, 11) are fixed.