An illumination device is provided and includes a light guide; a light emitting unit facing the light guide; a wiring substrate provided on the light emitting unit; and a frame surrounding the light guide and the light emitting unit, wherein the wiring substrate has a first edge and a second edge which extend in the first direction, and a third edge which connects the first edge and the second edge, the frame has a fourth edge facing the third edge; the third edge and the fourth edge are spaced apart from each other and form a trench which communicates with an outside of the illumination device, and a length of the third edge and a length of the fourth edge along the trench are larger than a distance between the first edge and the second edge in a second direction intersecting the first direction.