A retaining device is provided for an instrument, including at least one joint having at least two parts, and at least one drive unit associated with the joint designed to move the joint by driving at least one of the parts. The retaining device includes a securing device, which has a locking mechanism associated with the joint and a release unit that can be activated, wherein the locking mechanism interacts with the release unit such that the locking mechanism holds the joint in a locked position as long as the release unit is not activated. The securing device permits motion of the joint out of the particular locked position within a specified range of motion even if the release unit is not activated. A corresponding securing device for a retaining device and to an operating method for the securing device are also provided.
