The purpose of the present study is to clarify the effects of T-S type instability on the boundary layer developing along the convex surface experimentally and numerically, focusing on transition process from laminar to turbulent state in the rotating system with streamline curvature. The longitudinal velocity and turbulent intensity have been measured near the convex surface whose radius of curvature is 1000mm. When the Coriolis force acts away from the convex wall, the primary instability of T-S instability is enhanced.