The invention relates to a tubular medical instrument having a hollow shaft, a handle positioned on the proximal end of the shaft, and at least one tool actuation element that is positioned in the hollow shaft and has on its distal end a tool, wherein the tool actuation element can be coupled with at least one actuation mechanism of the handle to actuate the tool and wherein the tool actuation element and the hollow shaft can be detachably connected to one another by a coupling mechanism. To create a coupling mechanism that is essentially free of any play and is simple to operate, it is proposed with the invention that the stopping of the coupling mechanism between the tool actuation element and the hollow shaft should be dependent on the position of the tool.