To shorten the processing time of image data and to efficiently execute the management of the image data without increasing the number of files by providing plural image data files for storing image data and a managing file for managing the image data files.

This system is provided with an optical character reader(OCR) 1 as an input device, an OCR terminal 2 as a terminal for controlling the OCR 1, a host device 4 to be operated under program control, an image managing file 5 for storing the managing information of image data and first to n-th image files 6-9 for storing respective image data. The image managing file 5 preserves 'name of image file {including absolute path (code or the like designating storage place)}' and 'image data quantity to be reference' as the current object of write in a leading record. Then, the managing file 5 has an image data file specification code and address information and manages the image data files 6-9.