An information processing device includes: a casing including a side surface having an opening part and a bottom surface orthogonal to the side surface; a frame provided at the bottom surface; a disk drive main body capable of being attached to and detached from the frame through the opening part; a disk tray which is operable to hold a disk, is capable of being inserted into and drawn out of the disk drive main body through the opening part, and has a hatch operable to close the opening part when the disk tray is inserted in the disk drive main body; and a coupling part through which the frame and the disk drive main body are coupled to each other in the vicinity of the opening part.