A mounting apparatus includes a drive bracket, a maintaining plate and a mounting bracket, the drive bracket includes a bottom plate, a first side plate and a second side plate, a receiving space is defined among the bottom plate, the first side plate and the second side plate, the receiving space is divided into a top portion and bottom portion by the maintaining plate. The top portion is adapted to secure a first disk drive, the mounting bracket is secured to the bottom portion of the two portions and configured for securing a second disk drive that is smaller than the first disk drive.