PURPOSE: To selectively protect stored contents of individual storage units by managing data storage in a memory card in each storage unit and providing the indication indicating whether overwrite or erase of the storage unit is permitted or not in a DIR (directory) of a MAT (memory allocation table).

CONSTITUTION: Relations among storage units where a group of information related to one another are stored out of plural storage units are indicated by a MAT 18, and the storage unit where the first part of the group of information related to one another is stored out of plural storage units is indicated by a DIR 16. Either of the MAT 18 and the DIR 16 has the indication which indicates whether write and erase of each storage unit, which the MAT 18 or the DIR 16 is related to, out of plural storage units is permitted or not. Thus, stored contents in individual storage units are selectively protected.