Lighting device, display device and television device

A lighting device comprising:

• a light source;
• a light guide plate having an end surface as a light entrance surface and a plate surface as a light exit surface, the light entrance surface through which light from the light source enters the light guide plate, and the light exit surface through which the light exits the light guide plate;
• a light source board having a plate surface where the light source is arranged and that is opposed to the light entrance surface and has a square shape;
• a power feed relay portion arranged on the light source board and that relays power feed to the light source;
• and
• a heat dissipation member where the light source board is arranged and configured to dissipate heat generated from the light source, the heat dissipation member having a positioning hole that is through the heat dissipation member and with which the light source board is positioned with respect to the heat dissipation member, and the positioning hole corresponding to the power feed relay portion, the heat dissipation member having a hole edge portion around the positioning hole and the hole edge portion including two sides constituting a corner portion, the two sides being parallel to two sides of the plate surface of the light source board, respectively, and the two sides of the light source board constituting a corner portion of the plate surface of the light source board.