An image processing apparatus includes: an acquisition unit that acquires a radiographic image of a breast； and a derivation unit that derives a percentage of mammary glands of a breast image in the radiographic image acquired by the acquisition unit on the basis of an amount of incident radiation on a direct region which is a region directly irradiated with radiation without passing through the breast and an amount of incident radiation on a mammary gland tissue pixel obtained by a portion of the breast which is estimated to be composed of only mammary gland tissues in the radiographic image
