A disk drive includes an insert-and-eject device and a disk guide unit. The insert-and-eject device is used for inserting an optical disk into and ejecting the disk from the disk drive. The disk guide unit includes a rack and a slide member connected operably to the insert-and-eject device in such a manner that reciprocal movement of the disk guide unit along a first direction permits the slide member to drive the insert-and-eject device to insert and eject the optical disk from the disk drive. An emergency release device is mounted on the slide member, and includes a horizontal element movable along a second direction. The rack is formed with a retention groove such that the movement of the horizontal element along the second direction permits a part of the horizontal element extend within or exit the retention groove so as to couple the slide member with the rack or to disengage the slide member from the rack.