A surface light source unit includes a cold-cathode fluorescent tube, a light guide which receives light from the cold-cathode fluorescent tube and outputs the light, a back frame supporting the cold-cathode fluorescent tube and the light guide and including a projection used to position the light guide and the cold-cathode fluorescent tube, and a lamp holder including a holding portion which holds an end of the cold-cathode fluorescent tube, and a buffering portion provided between the projection and the cold-cathode fluorescent tube.