According to one embodiment, an illumination device includes a light guide, a frame surrounding the light guide, a light emitting unit located between the light guide and the frame, and a wiring substrate electrically connected to the light emitting unit. The wiring substrate includes a convex portion projecting in a first direction as seen in plan view. The frame includes a concave portion facing the convex portion as seen in plan view. The concave portion is spaced apart from the convex portion.