An erosion device and a corresponding method are disclosed for machining a hollow-cylindrical workpiece, wherein the device is elongated and/or formed in the manner of a tube or cylinder and is characterized in that at least two rotationally acting drives (A1, A2), each with a drive shaft (AW1, AW2), and also an erosion electrode (E), interacting with the drives (A1, A2) and formed in the manner of a ring or disc, are provided. The drives (A1, A2) and the electrode (E) are adapted in size and extent to the internal diameter of the workpiece (W) to be machined, so that the device can be introduced into the respective hollow-cylindrical workpiece (W) and can be positioned at the location respectively to be machined or the region to be machined in the workpiece (W), and the erosion electrode (E) can be pivoted or can be rotated by a coupled pivoting or rotating movement of the at least two drives (A1, A2).