An illuminating device includes a plurality of light source portions for emitting light, a plurality of optical fibers for allowing incidence of the light emitted from the respective light source portions, and a bundling portion for bundling exit ends of the optical fibers. The light source portions or the optical fibers are constructed in such a manner that a flexure of each of the optical fibers is suppressed to mount the each optical fiber in a state close to a straight state. For instance, the light source portions are arranged in an arc shape, with a distance of each of the light source portions with respect to the bundling portion being set as the radius of the arc shape. In this arrangement the respective optical fibers are set to have lengths substantially equal to each other.