Disclosed is a light guiding plate formed with fine recesses and a backlight unit utilizing the same. There are formed on a bottom surface of a transparent acryl resin substrate a number of fine recesses, which are unable to be distinguished with the naked eye, in order to reflect on front surface of the plate a source light introduced through at least one side surface. The fine recesses are formed by means of a sandblasting process. The amount of the fine recesses jetted per unit hour is uniformly maintained. The number of sands collided into unit area per unit hour and impact energy of the sands are higher the further away from the side through the source light is introduced. Accordingly, density, average depth and average size of the recesses are gradually higher the further away from the light introduced side. Also, area, average complexity of the contour of the recesses and average complexity of the surface profile of the recesses are increased. Therefore, as a light getting out of the front surface of the plate is uniformly diffused, a diffusion sheet is not needed in composing a backlight unit for an advertising film or a LCD panel by utilizing the plate.