Abstract: A sunshade includes an upright post with a runner sleeved slidably thereon so as to be movable to a stretching position for operating a rib assembly in order to stretch collapsibly a top cloth above the upright post. The upright post has a spring-loaded stopper which protrudes radially to retain the rib assembly at the stretching position. The runner has an axially extending groove formed in an inner surface thereof and aligned with the stopper, and a projection formed in the groove. The projection has an upper face which inclines inwardly and downwardly and a lower face which extends radially toward the post. The runner has a releasing unit mounted thereon. The releasing unit is constituted by a pressing member which is radially movably disposed in the groove immediately under the projection and a button member which is formed integrally with the pressing member. The button member protrudes out of the runner via a through-hole in the runner.