The mean flow and statistical property measurements have been made in the vicinity of the roughness element for a boundary layer over a d-type surface roughness. The results show that profile of the mean velocity and the turbulence intensity varies to be wavy in the similitude of the roughness geometry, due to the periodic nature of the present rough wall, and that both quantities rise fairy sharply at the region immediately above the grooves. The flow formed in the cavity is not completely independent of the external flow over the groove, and considerable exchange of fluid in the cavity with the boundary layer occurs. A discussion of some terms in both the momentum and the turbulent energy equations is given. From these results, the feature of present flow in the region near the roughness element has been clarified.