A blurred image generating section generates a plurality of blurred images Sm (where m=1 to n and n.gtoreq.2) different in frequency response characteristic from one another, based on an original image S0. A band-limited image generating section generates a plurality of band-limited images Tm by performing a subtraction between images of adjacent frequency bands, employing the original image S0 and each of the blurred images Sm. A noise component extraction section extracts converted images, obtained by performing nonlinear conversion on each of the band-limited images Tm, as noise components Qm contained in the different frequency bands. A noise-component elimination section subtracts from the original image S0 a value obtained by multiplying a subtraction coefficient .beta. (which is determined according to the pixel value Y0 of the original image S0) and the sum of the noise components Qm together.