A surface light-emitting lamp for a backlight unit is provided to dispose a sealing material within a small valley formed in an edge portion of an upper glass substrate when the upper glass substrate is bonded to a lower glass substrate, thereby maintaining uniform thickness of the sealing material. A plurality of furrow-shaped discharge spaces is formed in the middle of an upper glass substrate(10). Small valleys(12) are formed in both edges of the upper glass substrate. A lower glass substrate(20) is bonded to the upper glass substrate to define discharge channels of a surface light-emitting lamp. A sealing material(3) is formed in the small valley when the upper glass substrate and the lower glass substrate are bonded, thereby preventing bubbles and the leakage of the sealing material.
