A disk inserting/ejecting apparatus includes: a disk carrying device which carries a disk between an insertion/ejection slot to/from which a disk is inserted/ejected and a disk driving position; right and left detection levers which come into contact with the disk and move at the time of carrying the disk; and a mounting plate in which notches are formed, the notches positioning so that the positions of the right and left detection levers before the disk comes into contact with the right and left detection levers and the positions of the right and left detection levers after contact between the disk and the right and left detection levers is cancelled are different from each other.