The backlight unit 12 includes cold cathode tubes 18, a chassis 14, inverter boards 20, relay connectors 21, and covers 22. The chassis 14 houses the cold cathode tubes 18. The inverter boards 20 are arranged on a side of the chassis 14 opposite from the cold cathode tubes 18. The inverter boards 20 are configured to supply drive power to the cold cathode tubes 18. The relay connectors 21 are mounted to the chassis 14. The inverter boards 20 are connected to or disconnected from the relay connectors 21 in one direction along board surfaces thereof (the X-axis direction). The relay connectors 21 are configured to relay power from the inverter boards 20 to the cold cathode tubes 18. The covers 22 are arranged between the chassis 14 and the inverter boards 20. Each cover 22 includes a movable portion 22b attached to the chassis 14 so as to be movable along the connecting direction and the disconnecting direction of the inverter board 20 to the relay connectors 21 (the X-axis direction).