A fluorescent tube is prevented from being wrongly attached and broken when being attached, and luminance nonuniformity of backlight due to luminance difference generated in the tube axis direction of the fluorescent tube is reduced. In a backlight device (2), a plurality of fluorescent tube sets, each of which is composed of four fluorescent tubes (21) having electrodes (211) at the both ends and a pair of lamp holders (5) storing portions close to the both electrodes at the both ends of the four fluorescent tubes (21), and the fluorescent tube sets are driven by a pair of inverter circuit board. The backlight device (2) is provided with a power transmitting member (10), which is connected to electrodes (211) at the ends on one side of the two fluorescent tubes (21), for every two adjacent fluorescent tubes configuring the fluorescent tube set, gathers wirings (9) from the electrodes (211) at the ends and transmits power; and a conduction member (7), which is connected to the electrodes (211) on the other side of the two fluorescent tubes and permits a current to flow between the electrodes at the other ends. In the lamp holder (5), the power transmitting members (10) and the conductive members (7) are alternately arranged.