Experimental investigations were carried out on the coherent structures of turbulent boundary layers in flow with adverse pressure gradient and, in the vicinity of separation, extensive visual observations using hydrogen bubble technique have been performed. In a flow with adverse pressure gradient the size of the structures are larger, therefore more details were observed. By a suitable manipulation of the generation of hydrogen bubble time-lines some new results were obtained in observing plan views near the wall. (1) The long streaks downstream along the interface regions between low-speed and high-speed streaks are continually stretching and their velocity may be greater than that of high-speed streaks, and the hydrogen bubbles in the long streaks generally have a longer life. (2) The x, y-vortices (streamwise) were also observed along the interface regions between high-speed and low-speed streaks. (3) The z-vortices (transverse) were observed at the front of the high-speed regions.