A shaft rotating device (10) for rotating a shaft (14) of a medical instrument (12) about its longitudinal axis (18) relative to a handle (16) of the medical instrument (12) comprises an operating element (24) for rotating the shaft (14), the operating element (24) being arranged at a proximal portion (28) of the shaft and being in driving connection with the shaft (14) such that the shaft (14) is rotatable relative to the handle (16) against frictional forces. The shaft rotating device (12) further comprises a coil spring arrangement (32) having a surface (33) and being in frictional contact with a surface of a counterpart (36) for keeping the shaft (14) and the handle (16) rotationally stationary with respect to each other and movable against frictional forces. The coil spring arrangement (32) comprises windings (40) being wound around the counterpart (34) in a unique winding sense. The operating element (24) and the coil spring arrangement are in operational connection with respect to one another such that a torque (59) applied to the operating element (24) decreases the frictional forces, while the shaft (14) and the frictional element are in operational connection with one another such that a torque (60) applied to a distal portion (20) of the shaft (14) increases the frictional forces. (Fig. 2)
