A disk drive device has a configuration in which one of stepped parts defined by a circular recess for guiding a disc, formed in a disc tray is substantially flush with the bottom surface of the circular recess even in an area beyond the outer peripheral part of a disc so that no air cavity part facing the outer peripheral side surface of the disc is induced around the disc. Thereby, it is possible to aim at lowering cavity noise caused by the air cavity during high speed rotation and fluid noise caused by turbulence.