PURPOSE: To record a high-resolution image or a large-screen image without resolution deterioration by reading different image data of a following line from image data which is read previously from a first line at a specified interval for thinning out the data per line, writing the data which is read into a frame memory and projecting light to a photosensitive material for printing based on the data which is read.

CONSTITUTION: If, for instance, an exposure circuit is used three times, first only image data of such a line number as can be divided by 3 is read and then it is written into a frame memory. Next an image composed of thinned out data is displayed on a CRT 10 for exposure based on the image data written into the frame memory to perform the first exposure for printing. After this, image data of such a line number as leaving 1 after dividing it by 3 is read and its thinned out data is displayed after taking the same procedures as described above to perform the second exposure for printing. Then in the same manner, an image consisting of thinned out data such as leaving 2 after dividing it by 3 is displayed on the CRT for exposure 10 to perform the third exposure for printing. Thus the printing through exposure of the whole image is completed.