A cooling structure is designed for an electronic device including a plurality of fans causing cooling air, a plurality of electronic parts serving as heat sources, and a plurality of power source units, all of which are arranged inside the housing. The electronic parts are positioned in the downstream side of cooling air produced by the fans, while the power source units are positioned in the further downstream side of cooling air compared to the electronic parts. The power source units are spaced out from each other in the perpendicular direction to the cooling airflow direction of cooling air such that the power source units do not overlap with the electronic parts in the cooling airflow direction in plan view. The cooling structure prevents cooling air, which is temporarily warmed by the electronic parts, from directly flowing into the power source units, thus improving a cooling effect.