A computer readable medium, apparatus, and method for efficiently managing a space bitmap. A computer readable medium includes: a user data area on which user data is recorded; and a temporary disc management area on which a space bitmap indicating a recording status of recording and reproducing unit blocks of the user data area is recorded. The space bitmap includes header information for distinguishing an additional space bitmap from the space bitmap. The additional space bitmap is assigned when a space provided for the space bitmap is insufficient to represent the recording status of the recording and reproducing unit blocks of the user data area.