An optical disk loading final position detection device includes an optical disk guiding device, a delivery roll, a pair of detection bars provided with detection parts capable of freely rotating around respective rotary pivots, a support part, the middle of the support part being provided with an assorted part interacting with the detection bar, and a trigger bar. One end of the trigger bar is provided with a contact part for contacting the periphery of an optical disk, and the other end being connected to a control part. When the detection bars are rotating, the support part makes the trigger bar move towards the direction directly facing the central line, so, the trigger bar will not extrude out of the maximum outer diameter of the optical disk along the optical disk transport direction, so as to implement miniaturizing the optical disk playing device.