To obtain an automatic backup method which performs backup opera tion in units of jobs or paragraphs such as sections of data and gives a good feeling of use to operator by transferring and recording file contents in process to a file saving means in response to the instruction for the start of the backup operation.

An operator 1 sets a threshold value for determining the timing of automatic backup operation in advance with a threshold setting means 100. After this threshold value is set, the operator 1 starts a job, a job instruction detecting means 110 detects its job instruction, and a control means 130 integrates the detected value. The integrated numeral is compared by a control means 130 with the threshold value set by the operator 1 in advance and when the integrated value of the weighted job exceeds the threshold value, the start instruction for the backup operation is sent out. This start instruction is recognized by a backup means 30 and the file saving means 40 is made to update and save the file contents.