A backlight apparatus of a sidelight type includes a light guide plate having an incident face on a lateral face and a light source unit having a plurality of substrates. The plurality of the substrates are respectively disposed on the incident face side of the light guide plate such that each of substrate faces of the substrates is parallel with a light exit face of the light guide plate, and the substrates are adjacent to one another in a thickness direction of the light guide plate. A plurality of light emitting devices that emit light along the substrate faces are mounted in columns on each of the substrate faces of the plurality of the substrates such that emitting directions of the light emitting devices are directed to the incident face.