A backlight unit including: a light source that irradiates light; and a diffusing plate that diffuses the light irradiated from the light source, wherein the diffusing plate is provided with a first microlens of ellipsoid form, and a second microlens of ellipsoid form disposed in such a manner that long axes of the first microlens and the second microlens are approximately perpendicular to each other, and a long axis direction of the first microlens and a long axis direction of the light source are arranged approximately parallel to each other, and a long axis direction of the second microlens and the long axis direction of the light source are arranged approximately perpendicular to each other.