PURPOSE: To eliminate the formation of a poor image or make an image display which does not disturb other displays such as a character display when an image from a medium such as an electronic book is displayed on a screen of large possible display dot size.

CONSTITUTION: In the data reproduction system which makes a reproduction display by using a display means of possible display dot size larger than the size of image dots recorded in electronic book software as data such as the display device 38 of a word processor 30, a means 31 which performs arithmetic and control for displaying data read out to a reproducing means 10 on a display means 38 increases or decreases and supplies the dot size of the read image data to the display means 38. In another way, the dot size of the image data is increased or decreased and supplied to the display means together with character data.