A backlight unit includes a light guide member including an incident surface extending in a first direction and a light source unit which generates a light, provides the light to the incident surface includes a body member extending in the first direction to define a cavity therein and includes a light exit part defined in one side portion facing the incident surface and connected to the cavity, a first light source disposed in the cavity and including a laser diode generating a first light having a first color, and a second light source disposed in the cavity spaced apart from the first light source in the first direction and including a laser diode generating a second light having a second color where the body member provides a third light having a third color obtained by combining the first and second colors to the incident surface through the light exit part.