An X-ray imaging system comprises: an imaging unit for irradiating a subject with X ray at different angles while moving an X-ray source in one direction in tomosynthesis imaging, detecting the X ray with which the subject has been irradiated with a flat panel detector to acquire projection data of X-ray images taken at different angles; and an image processor for reconstructing a first X-ray tomographic image using projection data acquired by the imaging unit, the image processor including: a correction decision unit for selecting, according to a given selection condition, one of previously provided different corrections to be performed on the projection data; a first image correction unit for performing correction based upon the correction selected by the correction decision unit on the projection data; and a first image reconstruction unit for reconstructing the first X-ray tomographic image using the corrected projection data.