PURPOSE: To effectively use the non-volatile memory by comparing the upper limit value of the number of times of writing stipulated to be the maximum value of a writing frequency recording area corresponding to the whole record and judging whether or not the continuous use is possible with the unit of the record.

CONSTITUTION: Data are written to an object record 10 to write a data area and '1' is added to an update counting value held by a corresponding update counter 11. The value to hold the maximum value of the counter 11 is retrieved and read and the maximum value is obtained. The update counting value and a rewritable frequency stipulated at the non-volatile memory 1 are compared and it is judged whether or not the continuous use of the non-volatile memory 1 is possible. Then, the memory can be used up to the rewritable frequency with the unit of each record 10 and the utilization factor of the non-volatile memory can be raised.