The present invention removes a computer virus-infected benchmark file by re-creating the benchmark file referenced by a reference-source file. One or more clone files, which serve as reference files, reference a clone-source file, which serves as the benchmark file. In a case where it has been determined that the clone-source file is infected with a computer virus, only the clone file referencing the infected area is subjected to a virus check and repaired. A new clone-source file is configured based on the repaired clone file and the clone-source file (b). The old clone-source file, which is infected with the computer virus, is deleted (c).