Vehicle roller blind with simplified coupling mechansim of guide rails

The window roller blind for motor vehicles has a material web fastened by one edge to a rotatably mounted winding shaft and anchored by the other end on an extension profile. One end of the extension profile is guided in a guide rail (16) which on its end adjacent to the winding shaft is provided with a first plug-in means (81). A base unit (55) has a bearing unit (61) for one end of the winding shaft and also has an enclosure in which sits a coupling device (58) which has a second plug-in means which is complementary and connectable to the first plug-in means.