To generate a high-quality image by surely removing a peak-shaped noise by correcting data at a position where the absolute value of data of a differential image between an object image and an image shifted for one picture element exceeds a prescribed reference value.

When the peak-shaped noise for one picture element is generated respectively at the rise and fall of pixel data having prescribed width as shown in a figure (a), the differential image between the object image and the image shifted for one picture element as shown in a figure (b) is found and when that value exceeds a reference value ±L, it is detected as the peak-shaped noise. Next, a noise area is determined by judging whether a distance to the noise area near a peakshaped position X is longer than resolution or not. Then, concerning these peak-shaped noises, a reference data position for correction is set except the peak-shaped noise position X as shown in a figure (c), and data at the peak-shaped noise position X are corrected by extracting data at the reference position from a reference image. Then, image data are reproduced as shown in a figure (d).