According to one embodiment, an illumination device includes a lightguide, a light-emitting layer, a first reflector, a second reflector, and a third reflector. A distance between the first reflector and the second reflector is greater at a second position farther from the light-emitting layer than at a first position closer to the light-emitting layer. A distance between the lightguide and the third reflector is greater at a fourth position farther from the first reflector than at a third position closer to the first reflector. An emission portion for allowing emission of light emitted from the light-emitting layer is formed between the second reflector and the third reflector.