ILLUMINATION DEVICE

An illumination device includes a light-guide member having an annular shape provided with an incidence portion of a light in one portion, and illuminating the entirety by propagating an incident light; and a diffusion cover disposed on a side opposite to a light source relative to the incidence portion by interposing the light-guide member therebetween, and diffusing a light generated from the light-guide member. The diffusion cover includes a plate-shaped base portion covering the incidence portion side in the light-guide member, and a circular portion covering the remaining portions of the light-guide member by integrating an outer peripheral portion into the plate-shaped base portion.