According to one embodiment, an illumination device includes a first light guide, a second light guide and a plurality of light sources. The first light guide includes a first main surface, a second main surface facing the first main surface, and a first side surface connected to the second light guide. The first side surface further includes a first connection surface and a second connection surface. The first connection surface extends from an end portion of the first main surface to the second main surface and obliquely extends so as to move away from the second side surface. The second connection surface perpendicularly extends from an end portion of the first connection surface to an end portion of the second main surface.