To provide a flexible planar light source including discharge slender tubes arranged in parallel, enabling weight reduction.

The planar light source 1 includes the plurality of discharge slender tubes 11, 11, 11 filled with discharge gas which issues ultraviolet light with electric discharge, a flexible electrode support sheet (a first sheet), 13 on which the plurality of discharge slender tubes 11, 11, 11 are arranged in parallel, and a plurality of electrode pairs 12, 12, 12 provided between the electrode supporting sheet (the first sheet) 13 and each of the discharge slender tubes 11, 11, 11 for generating electric discharges inside the discharge slender tubes 11, 11, 11.