A mounting apparatus for mounting a plurality of expansion cards (50) in a computer includes a chassis (10), a rack (40), a fixing member (60), and a locking member (70). The chassis includes a rear panel (12). The rack is attached to the chassis and includes a fixing plate (42) parallel to the rear panel. The fixing member is attached to the fixing plate and pivotally secures ends of the expansion cards with cover pieces (53) to the rear panel. The locking member is rotatably attached to the fixing plate of the rack and includes a plurality of hooks (715) extending therefrom. The hooks engage in apertures (51) defined in the other ends of the expansion cards.