An endoscopic instrument system for performing endoscopic interventions via a natural access path, including a flexible endoscope with an endoscope handle and an elongate endoscope shaft introducible into a hollow space in a body, wherein the endoscope shaft includes a steerable end section and at least one instrument channel, and also includes an endoscopic instrument with a handle, an elongate instrument shaft and a tool which can be actuated by a pull and/or push element arranged within the instrument shaft and connected to the handle and to the tool, wherein the endoscopic instrument can be introduced into the instrument channel for conducting manipulations in the hollow space in the body, and wherein the instrument shaft includes a continuous flexible tube that is connected, such that it is rotationally fixed, to the handle and to the tool with respect to a longitudinal direction of the tube.