According to one embodiment, an illumination device includes a light source disposed along a first direction, a light guide plate including a first end and a second end, the second end being positioned to be opposite to the first end in a second direction which crosses the first direction, a frame disposed along the second end and including an inner surface and an upper surface, and an adhesion member disposed on at least the upper surface of the frame, wherein the light source is disposed at the first end along the first direction, at least the inner surface of the frame is a light absorbing surface, and the adhesion member is light transmissive.