A backlight unit 20 that radiates light toward a display panel 4 includes LEDs 22, a backlight chassis 21 that includes a rear surface side wall portion 21a that supports the LEDs 22, an insulating frame body 24 that forms a space covering a surface of the rear surface side wall portion 21a on the side opposite to the side on which the LEDs 22 are supported, a partition portion 24a that partitions a space inside the insulating frame body 24 into a plurality of regions, intake ports 24c that cause air to flow inside the insulating frame body 24, and exhaust ports 24d that cause air inside the insulating frame body 24 to be discharged, the intake ports 24c and the exhaust ports 24d being provided on the insulating frame body 24 so as to correspond to each of the regions partitioned by the partition portion 24a.