A mounting apparatus for fixing an expansion card to an expansion socket with two latching members pivotably mounted to opposite ends of the expansion socket to engage with the expansion card, includes two engaging blocks attached to the opposite ends of the expansion socket below the latching members, and a fixing bracket attached to a side of the expansion socket. The fixing bracket includes two latching portions respectively formed from opposite ends of the fixing bracket, to correspondingly latch the engaging blocks, thus making tops of the engaging blocks resisting against bottoms of the latching members to prevent the latching members from pivoting.