An embodiment of the present invention provides an illuminating device that is disposed in an image-reading apparatus and image-forming equipment, comprising: a light-source portion on one side; a light-source portion on the other side; and a long translucent light-guiding member having a light-discharging face long in a longitudinal direction thereof, and guiding light derived from the one light-source portion from one end face in the longitudinal direction, and light derived from the other light-source portion from the other end face in the longitudinal direction so that the guided light is irradiated to an object through the long light-discharging face; wherein the one and the other light-source portions are arranged such that positions of optical axes thereof differ from each other.