Planar lighting device with external connection section

A planar lighting device comprising:

• a board that includes a strip-shaped section, which has a strip shape, and an external connection section, which protrudes from a central part of the strip-shaped section in a lateral direction of the strip-shaped section, and that is provided with an installation surface, which is one principal surface, and a wiring surface, which is a surface at an opposite side of the installation surface;
• a plurality of light source units that are provided with a plurality of light sources connected in series, that are each provided with a first electrode and a second electrode on both end sides thereof, and that are arranged side by side on the installation surface at the strip-shaped section of the board in a longitudinal direction of the strip-shaped section, an emission surface of the light source being opposed to a side surface of a light guide plate;
• first wiring that is provided on the wiring surface of the board and that is commonly connected between the external connection section and the first electrode;
• and
• second wiring that is provided on the wiring surface of the board and that is connected between the external connection section and the second electrode, wherein
• the single external connection section is provided for the light source units, and
• the first electrodes in all the light source units, related to the single external connection section, are located farther from the external connection section than the second electrodes of the light source units.