A thin-type light illuminating apparatus with a heat radiation member having high heat radiation efficiency. The light illuminating apparatus for illuminating light in line shape extending in a first direction on an illumination surface includes an elongated substrate extending in the first direction, a plurality of light emitting diode (LED) light sources on the substrate, a heat transfer pipe extending in a second direction, and configured to transfer heat generated from the LED light sources in the second direction, a heat radiation sink having a plurality of heat radiation fins protruding in a third direction, an illuminator having a thin box shape and configured to house the substrate, the heat transfer pipe and the heat radiation sink and to form a wind tunnel, and a centrifugal fan in the second direction between the substrate and the heat radiation sink, and configured to draw air from outside into the wind tunnel.
