A spread illuminating apparatus includes: a light guide plate having protrusions on side surfaces of the light guide plate, a housing frame having recesses in which the protrusions of the light guide plate are introduced, a reflecting sheet arranged on a bottom surface side opposing an emitting surface of the light guide plate, and a fixation device for fixing the reflecting sheet to a bottom surface of the housing frame. The recesses of the housing frame include a first recess which is formed to be opened at a bottom surface side and is at least partially covered by the fixation device, and each of the protrusions to be arranged at the first recess has an opposing surface that opposes the fixation device, and the opposing surface is provided with clearance relative to the fixation device.