PURPOSE: To attain high speed display of an index image by recording the index image data continuously to a predetermined area and even by recording the data to a recording medium of a slow seek speed.

CONSTITUTION: When new image data GD obtd. by picking up a new object are stored in a frame memory, image number of a new GD main body is decided and stored in a GD storage area of a magneto-optical disk. An index IGD requires 12.5kbytes and 5 IGDs are stored per one cluster. The GD main body is not limited for a storage location especially in a GD storage area and the sequence of image storage is not limited. Each index image of the picked-up GD main body is continuously recorded to a predetermined area of the recording medium. Thus, number of times of seeking and transfer data quantity are minimized and even when the data are recorded in the recording medium whose seek speed is slow, the index image is displayed at a high speed.