Abstract: Disclosed is a straddling dowel, of plastic, having a continuous screw insertion hole and several expansion segments that are formed by longitudinal slits in the dowel body and which extend from the circular head portion to the circular foot portion of the dowel. In the latter part, a female thread can be cut by the inserted screw, thereby rendering axial expansion of the dowel body posible. The expansion segments are formed by overlapping annular plates or discs which, on spreading or axial expansion in the form of an increase in diameter or spreading move relative to each other over the whole extent of the contacting surfaces of adjacent plates or discs, which contacting surfaces run obliquely or conically to the axis of the dowel.