When a roller holder attached to a floating chassis of the disk player rotates to raise a carrier roller from a disk non-carrying position to a disk carrying position, a convex portion of the roller holder is engaged with concave portions of the main chassis from above so as to fix the floating chassis to the main chassis in the back and forth directions as well as the right and left directions. The roller holder further rotates about a fulcrum to raise the floating chassis. As a result, the floating chassis is made to abut against another part of the main chassis from below to fix the floating chassis to the main chassis in the vertical direction.