PURPOSE: To obtain a smoothed image containing a clear boundary by outputting selectively an original image or a smoothed image based on the edge area included in the original image.

CONSTITUTION: An output selecting device 5 transmits selectively the original picture element train given from an input device 1 or a smoothed processing picture elements received from a smoothing processing part 3 based on the picture element data given from a nearby information extracting part 4. Therefore the device 5 outputs the original picture element received from the device 1 to the picture elements corresponding to an edge and an area near the edge. Meanwhile the smoothed processing picture elements received from the part 3 are outputted to other picture elements. Thus an image can be smoothed with an edge area kept clear.