A recording/reproducing apparatus, for conducting edition works, such as, addition, movement, and deletion, etc., of data, onto a postscript type medium, defective management of which is conducted with using a replacement area, is disclosed. The apparatus includes a media information management unit. The medium management information is recorded by a renewal unit within a medium management information area. The apparatus further includes a replacement address information management unit. This is included within the medium management information. Furthermore, the apparatus includes an available number of times of edition works calculation unit. The available number of times of edition works calculation unit calculates the remaining available number of times of edition works, upon basis of remaining capacity of the medium management information area and renewal units thereof. Accordingly, display or notification of a correct available number of times of edition works to a user occurs.