A mounting device for a circuit card includes a motherboard adapted for receiving the circuit card inserted therein, a computer enclosure configured for accommodating the motherboard, a securing plate mounted on the computer enclosure, and a retaining member with a receiving slot. The retaining member slides along the securing plate and in parallel with one end edge of the circuit card to have the end edge of the circuit card received in the receiving slot. A locking structure is formed between the retaining member and the securing plate for locking the retaining member to the securing plate.