An information recording medium including a plurality of sectors of the present invention includes: a first spare area including a spare sector for replacing a defective sector among the plurality of sectors; a defect management information area for managing the replacement of the defective sector by the spare sector; and a volume space in which user data can be recorded. The volume space is configured so that a second spare area including a spare sector for replacing a defective sector among the plurality of sectors can be additionally allocated. Location information indicating a location of the second spare area is recorded in the defect management information area.