1. An image processing method adopted to remove noise present in an image, comprising: an image input step in which an original image constituted of a plurality of pixels is input; a multiple-resolution images generation step in which a plurality of band-limited images with resolutions decreasing in sequence are generated by filtering the input original image; a first noise removal step in which virtual noise removal processing is executed individually for each of the band-limited images; a second noise removal step in which actual noise removal processing is executed for the individual band-limited images based upon the band-limited images from which noise has been virtually removed through the first noise removal step; and an image acquisition step in which a noise-free image of the original image is obtained based upon the individual band-limited images from which noise has been actually removed through the second noise removal step, wherein: the virtual noise removal processing executed in the first noise removal step and the actual noise removal processing executed in the second noise removal step are differentiated in correspondence to a frequency band of a band-limited image.