A mounting apparatus includes a receiving tray receiving a data storage device, a rack receiving the receiving tray, a rotatable shaft, two pivoting members fixed to the rotatable shaft, two resilient members, and a cover detachably mounted to the rack. The clamping protrusion protrudes out from the receiving tray. The rotatable shaft includes a latching portion. The resilient members are mounted to the corresponding pivoting members, and each resilient member resists against the rack and the corresponding pivoting member. When the cover is mounted to the rack, the pivoting members are rotated together with the rotatable shaft. Therefore, the latching portion rotates to engage with the clamping protrusion, and the resilient members are deformed. When the cover is removed from the rack, the resilient members are released to rotate the pivoting members together with the rotatable shaft. The latching portion rotates to disengage from the clamping protrusion.