Takanori SAGA �Katsutoshi WATANABE �and Masaya NAKAGAWA This research aims to examine the status of the wind around a high-rise building. The flow structure and the properties of the flow velocity were analyzed by using the flow visualization techniques and PIV for a plane, side and streamwise views of the flow. The results of the analysis show that a horseshoe vortex larger than usual ones is formed in front of an object because of the existence of a high-rise building and that a mushroom type vortex different and stronger than usual ones is always formed in the wake region. It has been clarified that vortices of these two kinds are distinct causes that make the wind flow fairly fast.