PURPOSE: To easily refer/update a file in an on-line by providing a file definition means, a display means and an image rewriting means.

CONSTITUTION: The selected file 62 is opened in a file selection processing part 58, and a record key input picture is displayed on a work station 53 in a picture output control part 56. A record selection processing part 59 extracts a record concerned from the file 62 based on the key of the record which is inputted from the picture and which is to be referred and updated. A record display processing part 60 edits the record by a hexadecimal number and a character and displays the record display (reference) picture on the work station 54. At the time of update, a displayed record dump image is corrected as if it is an editor on the screen, and the record is corrected in a record update part 61, and it is rewritten into the file 62. Thus, the file can interactively referred and updated on a real time basis without being conscious of exclusiveness with the other application in the on-line.