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.