The operation and effect brought about by the cooling device 1 of the first embodiment is described in the following. The cooling device 1 includes a heat-generating component, a circuit board on which the heat-generating component is mounted, an external heat dissipater located above the heat-generating component so as to dissipate heat to the outside, and the graphite sheet 4 integrally provided on the heat-generating component side surface. The cooling device 1 includes the heat conductive portion 5 that contacts both a part of the graphite sheet 4 and the heat-generating component, and the shielding portion 6. The shielding portion 6 covers a surface of the graphite sheet 4 on the circuit board side, being disposed at a position between (i) a portion of the circuit board where no heat-generating component is mounted/disposed and (ii) the graphite sheet 4.