The present invention provides a memory card (1) using a write-once memory IC (17), such as PROM. In this memory IC (17), an entity data recording area, where the entity data of a file is recorded, and a management data recording area, where management data for supervising the recorded files in accordance with a hierarchical director structure is recorded, are formed at the outset. In the management data recording area, a file entry specifying the files recorded in the memory card (1), a root entry specifying the uppermost order director in the hierarchical directory structure and a sub-entry specifying sub directories in the hierarchical directory structure, are recorded as management data in association with the files, root directory and the sub-directories generated, respectively.