A rotatable tool handle comprises a first part and a second part which can be switched between an in-line position and an angle position. Further, the locking structure for fixing the first and second parts is disposed between the connecting structures of the first and second parts, so that the engaging points of the first and second parts lie on the rotation axis of the two parts. Moreover, the portion of the first part for forming the recess is harder than the rest of the first part, and the portion of the second part for forming the pivot portion is harder than the rest of the second part, so as to enhance the structural strength of the engaging structure of the first and second parts of the handle.