A light guiding plate includes a light guiding main body, a first light guiding unit and a second light guiding unit. The light guiding main body has a first surface, a second surface opposite to the first surface and a light inlet face connecting between the first and second surfaces. The first light guiding unit includes first and second light guiding structures disposed on the first surface. The first and second light guiding structures are parallel aligned, each second light guiding structure has a plurality of first light guiding bodies that is individually separating and connecting the immediately abreast first light structures, and the arrangement density of the plurality of first light guiding bodies decreases toward the light inlet face. The second light guiding unit includes a plurality of third light guiding structures disposed on the second surface. The third light guiding structures are parallel arranged.