A dismantlable surgical sliding shaft instrument having a function shaft comprising a guide element, a slide element supported on the guide element in a sliding manner and having a coupling element, an undercut rail oriented along the sliding direction of the slide element and having a mounting opening at the proximal end of the rail, a profile web having a profile complementary to the rail, a gripping part having a rear gripping element at an angle at the end of the guide element, a front gripping element pivotably supported on the guide element and having a carrier element to carry along the coupling element, and a securing device on the rear gripping element and engaging with a form closure component in the proximal part of the guide groove in a securing position, and a transition piece complementary to the form closure component between the distal part and the proximal part.