An exemplary rotational mechanism (100) includes a cable (14), a cable-protecting structure (16), a first member (12) and a second member (10) rotatable relative to each other. The cable is fixed relative to the second member. A first through hole (128) is defined in the first member. The cable-protecting structure includes a bearing (161). The bearing includes an inside ring (163) and an outside ring (164) rotatable relative to each other. The bearing is received inside of the first through hole. The outside ring of the bearing is fixed to the first member. The cable is spaced from a ledge (1282) formed the first through hole and supported by the inside ring of the bearing.