Abstract: A file revision management system for executing file revision management when an application operating on an operating system of a computer system saves a file by file overwrite includes a file manipulation monitoring section and a processing section implemented by memory-resident software, for example. The file manipulation monitoring section monitors and hooks API (Application Program Interface) commands outputted by the application to the operating system, and thereby detects file manipulation executed by the application. The processing section executes file manipulation necessary for file revision management (i.e., file deletion and file name change for generating a backup file) and processes necessary for file revision management, depending on the file manipulation executed by the application detected by the file manipulation monitoring section.