A device for cutting a plate of a pre-determined thickness, preferably a glass plate, and comprising: - A frame (10, 31); - A support device (12, 20) for a cutting utensil; - The support device (12, 20) being connected to the frame (10, 31); - said support device (12, 20) being mobile according to an extraction/retraction motion with respect to the frame and wherein a hinged lever system (32, 33, 34) is further comprised, having a feeler element, said hinged lever system being kinematically coupable with said support device (12, 20) in such a way as to bind it in a pre-determined initial position with respect to the frame and so that, when said feeler element is pressed against a surface, an operation of the hinged lever system is determined allowing the support device, starting from said initial position, to move forward an extraction motion; Characterized by the fact that the frame comprises a body and the support device comprises a rod being slidingly inserted in the body, a regulator device (40, 41-c, 41-b, 41-a) being fixed at the summit of the rod and on the opposite end of the rod being fixed a support on which in use to fix the cutting utensil, the regulator device comprising at least one regulator screw inserted in a receiving eyelet in such a manner that the regulator screw can be positioned at a pre-defined height, the lever system (32, 33, 34) comprising an L-shaped first lever rotatable fixed to the frame (10, 31), a third lever assembled slidingly into a guide and a second lever hinged by its ends respectively to the first lever and to the third lever in such a manner that a rotation of the first lever in a clockwise or in the counter-clockwise direction causes, through the second lever, a translation of the third lever toward a direction or toward an opposite direction along the guide, wherein first elastic means are further comprised and acting on the first lever in such a way as to keep said hinged lever system (32, 33, 34) in the starting position and, when a rotation of the first lever against the action of said first elastic means is applied, this rotation causes a translation of the third lever toward the bottom with respect to the guide and with said first elastic means exerting a returning force for moving the hinged lever system toward the starting position, wherein second elastic means are comprised and acting on the rod in such a way to exert a force on the rod leading to move the rod toward the extraction direction, the first and second elastic means being calibrated in such a manner that, when a regulator screw (41-a, 41-b, 41-c) rests on the head of the third lever, the rod and the lever are in equilibrium with a consequence that when a rotation of the first lever, causing a translation of the third lever toward the bottom, is applied the translation of the third lever is followed by an extraction movement of the rod and when a counter-rotation of the first lever caused by the first elastic means is applied this counter-rotation causes a rising of the third lever that pushes the rod via the regulator screw in the retracted position against the second elastic means. - A frame (10, 31); - A support device (12, 20) for a cutting utensil; - The support device (12, 20) being connected to the frame (10, 31); - said support device (12, 20) being mobile according to an extraction/retraction motion with respect to the frame and wherein a hinged lever system (32, 33, 34) is further comprised, having a feeler element, said hinged lever system being kinematically coupable with said support device (12, 20) in such a way as to bind it in a pre-determined initial position with respect to the frame and so that, when said feeler element is pressed against a surface, an operation of the hinged lever system is determined allowing the support device, starting from said initial position, to move forward an extraction motion;