Abstract: It is an optical disk apparatus which is equipped with a cover, a tray which is disposed in such a manner that it can be inserted into and pulled out from the cover, a spindle motor which is disposed on the tray and rotates an optical disk, and a carriage which is held on the tray in a movable manner and on which an optical device, which carries out at least one of recording and reproduction to an optical disk, is mounted and which comes close to and comes free from the spindle motor and, on a surface of the cover, which faces the carriage, at least one of a concave portion or a convex portion, which is of a nearly circular shape nearly concentrically with a center of the cover or of a polygonal shape nearly concentrically with a center of the cover, is disposed.