A removable disk drive apparatus can insert a smaller diameter disk into a tray of a vertical drive device, and improve the reliability of the disk supporting function. The tray, on which a plurality of concave portions for a disk for supporting disk storage media having different diameters are formed in the concentric positions, includes larger disk support lugs provided at plural points on the periphery of the concave portion for a larger diameter disk, and smaller disk support lugs provided at plural points on the periphery of the concave portion for a smaller diameter disk. The smaller disk support lugs include a storage groove provided at a plurality of points on the periphery of the concave portion for a larger diameter disk, flexible lugs with elastic deformation supported in the storage groove, and having tip portions projecting into the periphery of the concave portion for a smaller diameter disk, and a stopper for keeping the tip portions of the flexible lugs projecting above the surface of the periphery of the concave portion for a smaller diameter disk from the storage groove.