Embodiments of the present disclosure provide a backlight unit comprising at least one light emitting unit emitting light in a first wavelength band, a phosphor film exciting the light in the first wavelength band emitted from the light emitting unit to emit the light in the first to a third wavelength bands, a first reflective film disposed in a position corresponding to a rim of the phosphor film and causing to reflect the light in the first wavelength band, a second reflective film disposed adjacent to the first reflective film and causing to reflect the light in the second and third wavelength bands, and a dam disposed around the light emitting unit. A display device using the backlight unit is also provided.