Backlight device and liquid crystal display device

A backlight device comprising:

• a case having a bottom plate;
• a light guide having a first main surface as an emission surface, a second main surface opposed to the first main surface, and an incidence surface provided between the first main surface and the second main surface, the second main surface being arranged on the bottom plate;
• and
• a light source unit configured to emit light to the incidence surface and comprising a wiring board with a wiring line and a plurality of light-emitting elements mounted on the wiring board, wherein
• each of the light-emitting elements has a mounting surface mounted on the wiring board, a first side surface provided at a bottom of each of the light-emitting elements and opposed to the mounting surface, and a light-emitting surface provided between the mounting surface and the first side surface, and
• each of the light-emitting surfaces faces the incidence surface,
• each of the first side surfaces and the second main surface are arranged side by side, and
• the light source unit is fixed to the light guide with a fixing tape attached over each of the first side surfaces of the plurality of light emitting elements and the second main surface of the light guide, while a gap is provided between the wiring board and the light guide.