To extend a product life of a non-volatile memory by eliminating the necessity of deleting excessive data in a FCB area for preventing the FCB area from being damaged.

A CPU 2 controlling a flash ROM 1 rewrites values of predetermined addresses possessed by a data area 10 that are to be assigned to respective addresses possessed by a first FCB area 11 of a first block B1 among a plurality of blocks B1 to B100 configuring the flash ROM 1, and values of predetermined addresses possessed by a second FCB area 12 of the first block B1 that are to be assigned to each of the plurality of blocks, by representing the values in four values "8","C","E", and "F" among the 16 types of values "0 to F" representing 4 bits in hexadecimal notation, and putting the values in order of "F" → "E" → "C" → "8". Also, at least the first FCB area between the first and second FCB areas is arranged by dividing the first FCB area into a plurality of blocks.