1. An image restoration apparatus for reducing a blur developed in an image generated by synthesizing a plurality of input images that are sequentially captured, said image restoration apparatus comprising: a PSF obtaining unit configured to obtain a first Point Spread Function (PSF) showing blurs which develop across the input images; a PSF transforming unit configured to process the first PSF to generate a second PSF, the processing being executed so that, in a frequency domain, an amplitude value for each of frequencies is not smaller than a threshold value; an image converting unit configured to convert the input images into a plurality of converted images based on portions (i) of the second PSF and (ii) each corresponding to one of the input images; and an image restoring unit configured to restore a degraded image, into which the converted images are synthesized, to generate a restored image, the restoration being executed based on the second PSF.