PURPOSE: To use a reducing circuit and a compressing circuit in common and to display a reduced image which is faithful to a read image by using a reduced image halfway in hierarchical encoding for a display image

CONSTITUTION: When read information from a reader 1 is compressed by a hierarchical encoding method by using a reducing and encoding means 3 and memories 3 and 6, 7 and recorded on a magnetooptic disk 9, the reduced image obtained halfway in the hierarchical encoding process by the reducing and encoding means 3 is stored in a video RAM 4 and displayed on a display unit 5. On the display unit 5, the reduced image which is faithful to the read image can be displayed and the read quality can acurately be judged, and an image which is read deficiently can easily be found and reread.