Abstract: A mounting device for mounting hard disk drives (10) includes a base (50), a bracket (40) mounted on the base, and a hard disk case (20) installed in the bracket. The bracket includes a plurality of clapboards (43). Each of the clapboards includes a plurality of guiding portions (423) formed thereon and a tab (421) stamped therefrom. The hard disk case includes a pair of guiding walls (24) and a latch (234). The guiding portions and the guiding walls cooperatively guide the hard disk case to correctly sliding into or out of the bracket. When the latch of the hard disk case is engaged with the tab of the bracket, the hard disk case together with the hard disk drive is locked in the bracket.