An information recording device is provided, which is capable of performing physical reformatting at a high speed while avoiding unnecessary substitution processing after the physical reformatting. A disc recording and reproduction drive 1020 records information on an information recording medium including a volume space for recording user data, a spare area containing a substitute area that can be used instead of a defective area, and a defect management information area for recording defect management information. The defect management information includes defect location information indicating the location of defective areas and defect status information indicating the attributes of the defective area. The information recording device includes an initialization processing module 1072 which, during the physical reformatting of the information recording medium, while maintaining at least the defect location information portion of the defect management information, overwrites said defect status information with attributes indicating that said defective area has been physically reformatted.