An X-ray imaging apparatus includes an X-ray source configured to radiate X-rays to a region of a subject, an X-ray detector configured to acquire a plurality of frame images related to the region of the subject by detecting the radiated X-rays, a filter configured to filter the X-rays radiated from the X-ray source, an image processor configured to set a region of interest within the region of the subject based on the plurality of frame images, and a controller configured to control the filter so that X-rays of a lower dose than a dose of X-rays made incident on the region of interest are made incident on a region of non-interest within the region of the subject, and control the X-ray detector so that a gain of the X-ray detector in the region of non-interest is greater than that in the region of interest.