PURPOSE: To perform an effective use of a tape and to provide a library control function by dividing a cassette tape into plural blocks with a specific length, determining the number of blocks in accordance with the length of a recording material and block controlling each material.

CONSTITUTION: A cassette tape is divided into plural blocks with a specific length and the number of blocks to be used is determined in accordance with the length of materials CM1 to CM4 which are to be recorded. The blocks which are once recorded are converted by performing an eliminating process to re-recording enable blocks.re-recording unbale blocks based on the block reproducing numbers. Even though an eliminating process is performed, the number of reproducing in the blocks is kept. Moreover, in regard to the plural blocks, to which materials are once recorded, the same block number is used to record during a re-recording.