Media writing additional information for defect management and defect management method

PURPOSE: A method for performing defect management is provided to replace an ECC(Error Correction Code) block with a defect by an original defect management system, and to move a reference block including the ECC block with the defect to an unused area, then to store additional information for defect management of the moved reference block. CONSTITUTION: A medium has a reserved area for defect management and a user area for writing A/V data. The medium checks whether an error is detected while writing the A/V data with reference block units. A data block having a defect is moved to the reserved area by a predetermined defect management system. A reference block including the data block having the defect is moved to an unused area. Additional information for defect management of the moved reference block is stored in a predetermined information area.