An uneven surface portion is formed on the inner surface of a lamp holder to thereby reduce the contact area between the inner surface of the lamp holder and a light incident face of a light guide plate. The light incident face of the light guide plate and the inner surface of the lamp holder are prevented from coming into close contact with each other due to heat transferring from cold-cathode fluorescent tubes and to the light guide plate. The heat transferring via the lamp holder to the light guide plate is intercepted by an air layer occurring between the uneven surface portion of the lamp holder and the light incident face of the light guide plate. Accordingly, it can be prevented that a part of the lamp holder sticks to the light incident face of the light guide plate of the backlight when the lamp holder is replaced.