A light source unit capable of obtaining white light with reduced color irregularity includes a plurality of light-emitting diodes (25R, 25G and 25B) having different emission spectrum peak wavelengths, and a light mixing member (21) that receives lights from the light-emitting diodes through an entrance surface (21a) and that allows lights to mix together before exiting through an exit surface (21b). The light mixing member (21) has anisotropic diffusing elements (22) that diffuse incident lights from the light-emitting diodes in a specific plane to effect light mixing.