An apparatus is provided in which a recording area is effectively utilized even when information-deleted portions and/or information-moved portions are provided on an information recording medium. The apparatus includes a space extent management section which recognizes and manages space extents, an optimization processing section which creates a coupled extent by coupling a information-deleted portion and a space extent in a condition that the above extents are adjacent to each other and optimizes the coupled extent as one space extent to be used for recording, and an extent arrangement processing section which arranges and manages the space extents according to a preset rule.