We carried out an experimental study about the effect of dimple of golf ball in the flight. In order to investigate the transition between a laminar boundary layer and turbulent boundary layer, the flow pattern close to the critical Reynolds number was examined in the experiment. The experiment was carried out for the flying ball with particle image velocimetry (PIV). Under the condition, we can obtain velocity profile under the ideal experimental condition without any obstacle or exclusive experimental requirement, such as ball support, turbulence of main flow. The experimental results show the characteristic velocity deviation in the boundary layer near the separation point.