1 A sun shield for automobiles comprising: a main rod  one end portion of which has a joint fixed thereon  the rod having three runners slidably sleeved thereon  said runners herein being referred to as first runner  second runner and third runner according to their position relative to the joint  between the joint and the second runner having locking means mounted on the rod for detachably locking the first runner  a plurality of main ribs radially extended from the axis of the main rod  each main rib being assembled from at least two sub-units which are slidably and stretchably telescoped on one another  one end of each main rib being hinged in said joint  the other end of the same herein being referred to as free end  a plurality of auxiliary ribs correspondingly mounted with the main ribs  one end of each auxiliary rib being hinged in said first runner  the other end of the same being hinged in a corresponding main rib  at least three legs isometrically extended from the axis of said main rod  one end of each leg being hinged in said second runner  the other end of the same having a sucker hinged thereon  at least three supporting ribs correspondingly mounted with the legs  one end of each supporting rib being hinged in said third runner  the other end of the same being hinged in the corresponding leg  and a flexible cloth disposed over the main ribs which is fixed at its periphery to the free ends of said main ribs  the size of said cloth being capable of entirely covering the main ribs while the main ribs are in a stretched state