To provide an information storage system by a flash memory for storing data for rank change of information or the data of the lapse time of information (since the information is stored in a flash memory) or data showing a user's access to the information in the flash memory together with the information, and for changing those data without erasing any block, and for managing information in terms of the storage of information in the flash memory.

In an information storage system by a flash memory for storing information, and for rewriting or erasing the stored information as necessary, specific bits in the specific region of the memory relating to the information are rewritten from 1 to 0, so that the meaning of the stored information can be changed.