A line illumination device includes: a frame; a rod-shaped light-guiding member housed in the frame; a flexible substrate; and a light source that is provided on the flexible substrate and emits light to the light-guiding member. The flexible substrate is bent so that the light source is disposed at an end of the light-guiding member and that the flexible substrate is housed in the frame. Power is supplied to the light source through a wiring provided on the flexible substrate so that the light source emits light and the light-guiding member emits light in line-shape.