The disc device that includes a disc tray which stores a plurality of stacked discs, a tray carrier which transports the disc tray, and a disc selector which supplies one disc of the plurality of discs stacked on the disc tray to a drive unit. The disc selector includes a disc selector spindle that supports the plurality of discs, a disc press on which an upper surface of an uppermost disc of the plurality of discs supported by the disc selector spindle abuts, a displacement amount detection mechanism that detects a displacement amount of the disc press displaced according to thicknesses of the plurality of supported discs, and a thickness detection unit that detects a thickness of each of the plurality of discs based on the detected displacement amount of the disc press.