The image processing apparatus according to the present invention includes a pixel extraction section that extracts an extraction region made up of a target pixel and a plurality of pixels included in a region peripheral to the target pixel, a similitude calculation section that calculates similitude of each pixel value in the peripheral region with respect to a pixel value of the target pixel, a similitude filter processing section that performs filter processing on the similitude, a first filter determining section that determines a first filter used in the filter processing of the similitude filter processing section, a second filter determining section that determines a second filter used for the extraction region based on the similitude subjected to the filter processing by the similitude filter processing section, and a noise reduction processing section that performs noise reduction processing on the target pixel based on the second filter determined by the second filter determining section.