The invention relates to a machining device (D) such as a device associating a machine-tool (100) with a workpiece holding device (200) having an axis about which the workpiece is rotated transversally (A) in relation to the downward axis (Z), the workpiece to be machined (300) being a long workpiece such as a workpiece comprising surfaces to be machined that are concentrated at the two ends thereof. Said machining device is characterised in that the workpiece holding device (200) consists of a frame (210) supporting two guiding bearings (220 and 230) for rotatably guiding the workpiece according to the transversal rotation axis (A), the structure formed by the frame (210) and the two bearings (220 and 230) being closed by the workpiece to be machined (300) by fixing the ends of the workpiece to the bearings (220 and 230). The invention also relates to a method for machining long workpieces. |