When processing bone tissue, the work site is often out of alignment with the insertion path of a tool device. A tool device (1) is provided with an endoscope (2), through the working channel (2.1) of which a guiding part (3) and a tool part (5) guided in this can be moved with their distal ends to a distal working area. The tool part (5) has a tool shaft (5.1) with a rotating tool (5.3). In the tool device there is a secure connection between the endoscope and the guiding part, during the task, and, this connection can be established in a simple manner prior to the beginning of the task and it can also be released again in a simple manner after the task ends. The guiding part (3) is able to be connected rigidly with the endoscope (2) axially.
