A mounting device (10) is for mounting expansion cards with cover plates (30) to a card cage (60) of a rear panel (80). Each cover plate includes an elongated portion (32) and a bent portion (34). The mounting device includes an elongated main body (12) with one end pivotally attached to the card cage, and the other end locked to the rear panel. A plurality of resilient fingers (122) is formed at an inner face of the main body for pressing the bent portions of the cover plate. A flexible pressing post (126) extends outwardly from a free end of each finger. A cover panel (90) is attached to the rear panel and presses the pressing posts to further secure the cover plates.