A supporting member usable with a backlight unit of an image display apparatus includes a supporting portion that is formed of a transparent material, disposed below a diffuser plate to support the diffuser plate, and includes a first end being in contact with the diffuser plate and two flat side surfaces disposed in parallel to one another and connected to one another at the first end; a base that is formed at a second end of the supporting portion and fixes the supporting portion to an under chassis of the backlight unit; and a reinforcing portion that is disposed on a top surface of the base.