A backlight unit , comprising: a light guiding plate ; an LED assembly ; and a bottom cover on which the LED assembly and the light guiding plate are provided, characterized in that the backlight unit further comprises: at least one first protruding portion protruding from the bottom cover ; and at least one second protruding portion protruding from the bottom cover , wherein the LED assembly includes: a plurality of LED light sources ; a substrate on which the plurality of LED light sources are mounted; and a support on which the substrate is mounted, wherein the support of the LED assembly has an L-shaped cross-section including: a vertical portion; and a horizontal portion; wherein a first hole and a second hole are each formed in the horizontal portion of the support , wherein the substrate is mounted on the vertical portion of the support , wherein the plurality of LED light sources are of a top view type emitting light to the top of the LED light source in the direction of the light guiding plate , wherein the first protruding portion is inserted in the first hole and protrudes further upwards to support the light guiding plate , and wherein the second protruding portion is inserted in the second hole to couple the LED assembly to the bottom cover . a light guiding plate ; an LED assembly ; and a bottom cover on which the LED assembly and the light guiding plate are provided, characterized in that the backlight unit further comprises: at least one first protruding portion protruding from the bottom cover ; and at least one second protruding portion protruding from the bottom cover , wherein the LED assembly includes: a plurality of LED light sources ; a substrate on which the plurality of LED light sources are mounted; and a support on which the substrate is mounted, wherein the support of the LED assembly has an L-shaped cross-section including: a vertical portion; and a horizontal portion; wherein a first hole and a second hole are each formed in the horizontal portion of the support , wherein the substrate is mounted on the vertical portion of the support , wherein the plurality of LED light sources are of a top view type emitting light to the top of the LED light source in the direction of the light guiding plate , wherein the first protruding portion is inserted in the first hole and protrudes further upwards to support the light guiding plate , and wherein the second protruding portion is inserted in the second hole to couple the LED assembly to the bottom cover . at least one first protruding portion protruding from the bottom cover ; and at least one second protruding portion protruding from the bottom cover , wherein the LED assembly includes: a plurality of LED light sources ; a substrate on which the plurality of LED light sources are mounted; and a support on which the substrate is mounted, a plurality of LED light sources ; a substrate on which the plurality of LED light sources are mounted; and a support on which the substrate is mounted, wherein the support of the LED assembly has an L-shaped cross-section including: a vertical portion; and a horizontal portion; a vertical portion; and a horizontal portion; wherein a first hole and a second hole are each formed in the horizontal portion of the support , wherein the substrate is mounted on the vertical portion of the support , wherein the plurality of LED light sources are of a top view type emitting light to the top of the LED light source in the direction of the light guiding plate , wherein the first protruding portion is inserted in the first hole and protrudes further upwards to support the light guiding plate , and wherein the second protruding portion is inserted in the second hole to couple the LED assembly to the bottom cover . <EOS>