According to one embodiment, an illumination device includes a first light emitting element, a second light emitting element, an overcoat layer covering the first and second light emitting elements, a first transparent block disposed on the overcoat layer and overlapping the first light emitting element, a second transparent block disposed on the overcoat layer and overlapping the second light emitting element, and an optical sheet group disposed on the first transparent block and the second transparent block. A first side surface of the first transparent block and a second side surface of the second transparent block face each other. An air layer is interposed between the first side surface and the second side surface.