A disk drive includes an insert-and-eject device and a disk guide unit. The insert-and-eject device is used for inserting and ejecting a disk. The disk guide unit includes a rack and a slide member connected 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 the horizontal element to 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.