PURPOSE: To simplify the preparation of the retrieval item by an image and to attain the high speed of the preparation by surrounding image data by the frame of a prescribed area and using this surrounded part as a retrieval image item at the time of performing a document retrieval.

CONSTITUTION: When a document retrieval is selected, image data for retrieval is acquired from an optical disk and is stored in a VRAM 5. Next, the data of a frame data group is acquired, a rectangular frame or a retrieval solution image item is formed in the VRAM 5 and the content of the VRAM 5 is displayed. When the retrieval conditions exist in the content of the VRAM 5 and the retrieval image item is selected in the content of the VRAM 5, the retrieval image number is acquired and a document having the same retrieval image item number in retrieval data is retrieved. Thus, the preparation of the retrieval item by image can be simplified and the high speed of the preparation can be attained. The versatility and the degree of freedom of the preparation of retrieval image items can be secured and further, the retrieval operation can be improved by diversifying the retrieval means.