An image processing device includes: an acquisition unit that acquires plural projection images captured by applying radiation from multiple directions, while moving a radiation applying unit, with respect to an object between the radiation applying unit and a radiation detector and by detecting the radiation via the radiation detector a tomographic image generating unit that generates tomographic images of the object by reconstructing them from the acquired plural projection images a projection image mask generating unit that generates plural projection image masks for separating an object region and a direct incidence region of each of the plural projection images a tomographic image mask generating unit that reconstructs and generates, from the plural projection image masks, tomographic image masks for separating the object region and the direct incidence region of the tomographic images and a masking unit that performs masking by applying the tomographic image masks to the tomographic images.
