A display apparatus comprising: a display panel, the main surface thereof extending in a first direction and in a second direction perpendicular thereto; a plurality of light sources arranged in the first direction, and configured to generate light to be transferred to the display panel along a third direction perpendicular to the first and second directions; a light guide plate having a side onto which light generated by the plurality of light sources is incident, and a light exit surface through which the light is transmitted to the display panel; a light conversion unit disposed between the plurality of light sources and the side of the light guide plate, and configured to convert a property of the light generated by the plurality of light sources; a heat dissipation holder in which the light conversion unit is mounted, and configured to dissipate heat generated by the plurality of light sources and the light conversion unit; a printed circuit board comprising a first portion, the main surface thereof extending in the first and third directions, and a second portion, the main surface thereof extending in the first and second directions, the first portion having a first surface on which the plurality of light sources are disposed, the first surface facing the light incident side of the light guide plate; and a heat sink disposed on a second surface of the second portion of the printed circuit board, the second surface being located in a direction away from the light guide plate, wherein the heat dissipation holder includes a pair of heat dissipation frames disposed above and below the plurality of light sources, the heat dissipation holder further comprises at least one extension member extending from one heat dissipation frame (111, 112) of the pair of heat dissipation frames in the third direction so as to be in direct contact with the heat sink, and the light conversion unit is disposed on a path of light toward the light guide plate from the plurality of light sources, between the pair of heat dissipation frames, wherein the second portion of the printed circuit board includes at least one heat dissipation hole formed adjacent to the heat dissipation holder, and the at least one extension member is accommodated in the at least one heat dissipation hole to be in direct contact with the heat sink. a display panel, the main surface thereof extending in a first direction and in a second direction perpendicular thereto; a plurality of light sources arranged in the first direction, and configured to generate light to be transferred to the display panel along a third direction perpendicular to the first and second directions; a light guide plate having a side onto which light generated by the plurality of light sources is incident, and a light exit surface through which the light is transmitted to the display panel; a light conversion unit disposed between the plurality of light sources and the side of the light guide plate, and configured to convert a property of the light generated by the plurality of light sources; a heat dissipation holder in which the light conversion unit is mounted, and configured to dissipate heat generated by the plurality of light sources and the light conversion unit; a printed circuit board comprising a first portion, the main surface thereof extending in the first and third directions, and a second portion, the main surface thereof extending in the first and second directions, the first portion having a first surface on which the plurality of light sources are disposed, the first surface facing the light incident side of the light guide plate; and a heat sink disposed on a second surface of the second portion of the printed circuit board, the second surface being located in a direction away from the light guide plate, wherein the heat dissipation holder includes a pair of heat dissipation frames disposed above and below the plurality of light sources, the heat dissipation holder further comprises at least one extension member extending from one heat dissipation frame (111, 112) of the pair of heat dissipation frames in the third direction so as to be in direct contact with the heat sink, and the light conversion unit is disposed on a path of light toward the light guide plate from the plurality of light sources, between the pair of heat dissipation frames, wherein the second portion of the printed circuit board includes at least one heat dissipation hole formed adjacent to the heat dissipation holder, and the at least one extension member is accommodated in the at least one heat dissipation hole to be in direct contact with the heat sink.