A backlight unit includes a light source capable of emitting light, and a light guide plate including a peripheral surface on which the light from the light source is incident, a main surface provided to be connected with the peripheral surface, and a main surface facing the main surface with the peripheral surface interposed therebetween, the light guide plate including a reflection surface capable of reflecting the light that has entered from the peripheral surface toward the main surface, and a lens formed on the main surface capable of condensing the light reflected by the reflection surface and emitting the light to outside.