1. A data management apparatus for supervising a non-volatile memory having a plurality of blocks erasable in a lump, each of said blocks being formed by a plurality of pages, each of said pages including a redundant area, said apparatus comprising management means for storing the distributed management information, as the management information for the respective blocks, in said redundant area of each page, and for storing the aggregate management information in said non-volatile memory, in association with said distributed management information, said aggregate management information supervising data stored in said non-volatile memory in a lump, said management means verifying, at the time of booting, whether said aggregate management information is effective, said management means supervising said data based on said aggregate management information when said aggregate management information is effective, said management means supervising said data based and on said distributed management information when said aggregate management information is not effective.