PURPOSE: To obtain a file recovery system which unnecessitates an auxiliary storage device for a back-up file and a data updating work after copying from the back-up file for recovery a file into a file state just before generating a fault.

CONSTITUTION: To a file prepared on a hard disk 11 with the instruction of a work program execution means 2, a file preparation means 4 adds a unique identification data, a record through number management means 5 adds through numbers to respective records constituting the file and a record updating means 6 prepares the file through the use of identification data and the through numbers. Consequently, even when a fault is generated in a hard disk control part 12, a file recovery means recovers the file through the use of identification data and the through numbers as keys after the fault is recovered.