Abstract: The present invention refers to a grooving device comprising grooving means for realizing a grooving line on a sheet, said grooving means comprising: —A first and a second blade-holder support arranged one opposite the other in such a way as to allow the application of a first and of a second blade, one facing the other according to a pre-determined penetration angle (tt) in the sheet, said first and said second blade-holder support being eliding in such a way as to allow a lowering/lifting of the blades that can be applied on them; —An operating device for controlling the sliding of said first and second blade-holder support, said operating device comprising a piston that alides in the grooving device and a pair of fixing pins, each one fixed on one part to a respective blade-holder support. In accordance with the invention, on the opposite part, said pins are maintained in contact in a sliding manner along a surface of the piston.