The flow around a semi-infinite circular cylinder placed at various spacings to a flat plate has been investigated experimentally. The cylinder was aligned with its axis normal both to the flat plate and to the free stream. Then, the pressure distributions along the plate and on the cylinder surface were measured and the velocity distributions were measured in the field of the flow behind the cylinder. The flow patterns on the plate and on the end face of the cylinder were visualized using the oil-film-technique, and the flow visualization around the cylinder was done by using the liquid-parafine-mist-technique. When the spacing was small, three flow patterns were observed around the cylinder : a horseshoe-like vortex, a symmetrical vortex and a Kaman vortex ; and one or two separation points along the plate were observed, too.