A machine tool is provided with a bit-changing apparatus including a cam, a rocker, a roller, a linkage, a pulling element, a disc and clips. The cam is attached to the machine tool. The roller is attached to the rocker and movable against the cam. The linkage includes two connecting rods each formed with an end pivotally connected to the machine tool and another end pivotally connected to the rocker. The pulling element is provided between the rocker and the machine tool so that the roller is kept against the cam. The disc is rotationally supported on the rocker. Each of the clips is attached to the disc and used to clip a holder for holding a bit so that a selected bit can be engaged with a bit-driving unit of the machine tool.
