PURPOSE: To set and display the window condition of a correct value at every image data and to automatize the operation required for setting by normalizing an image obtained by a scanner by using a peak value of echo data, or correcting and setting the display window condition by a size of collection data at the time of displaying an image.

CONSTITUTION: A controller 13 sends out echo data from a scanner 11 and an echo data peak value from an echo data peak value detector 12 to a reconstituting part 14. The reconstituting part 14 generates image data by echo data with a reconstitution arithmetic processing, and thereafter, normalizes all pixel data of the generated image data by using the echo data peak value. The normalized image data is stored in an image file device 15 constituted of a magnetic disk device and an optical disk device together with each of various incidental information, and on the other hand, converted to a display window by a window converter 17 in accordance with an operating instruction by a keyboard 16, and displayed and outputted by a display device 18.