Synchronizing device as well as a gear changing transmission for a vehicle

Synchronizing device (1) of a gear changing transmission for a vehicle. The synchronizing device includes an inner synchronizer ring (2), a middle synchronizer ring (3) and an outer synchronizer ring (4), wherein in the operating mode the outer synchronizer ring (4). The inner synchronizer ring (2) includes a first conical inner ring body (201) with a first inner surface of the inner ring (2011) and a first outer surface of the inner ring (2012), which each bound the first inner ring body (201) in a radial direction extending to an axial ring axis (8), wherein the first inner surface of the inner ring (2011) extends at a first inner angle (α2011) of the inner ring and the first outer surface of the inner ring (2012) at a first outer angle (α2012) of the inner ring to the ring axis (8). In order to further increase the synchronizing moment to be transmitted the first inner angle (α2011) of the inner ring is smaller than the first outer angle (α2012) of the inner ring according to the invention.