The motion of wind-blowing sand grains was photographed by a high speed digital imaging camera in a large wind-tunnel under the realistic conditions. Well-sorted sands taken from a natural beach and sieved with median diameter of 0.15, 0.25, 0.52, 0.68 mm were employed. The vertical distribution of wind speed and the horizontal component of flying sand grains velocity were followed by the logarithmic law. Then the vertical distribution of the ratios for the horizontal component and wind speed also followed by logarithmic law and the gradient of curves was almost the same for four kinds of sand. For the sand with median diameter of 0.68 mm, obtained were approximate values of 2.0 m/s and 10-20 degrees for the falling velocity and angle and approximate values of 1.0 m/s and 20-50 degrees for rebound velocity and angle.