A data storage device includes a nonvolatile memory device including a plurality of memory blocks; a random-access memory including a bad block management module configured to register and manage bad blocks included in the plurality of memory blocks; and a processor configured to detect primary bad blocks by performing a primary bad block scan operation on the plurality of memory blocks using the bad block management module, detect secondary bad blocks by performing a secondary bad block scan operation on normal memory blocks other than the primary bad blocks among the plurality of memory blocks, and register the detected primary bad blocks and the detected secondary bad blocks as bad blocks.