Provided is a method of removing a moir in a fluoroscopic X-ray image that preliminarily complements a defective pixel with no disturbance in regularity of a moir pattern to ensure that no trace of the defective pixel and no ghost thereof create even when the fluoroscopic X-ray image contains the defective pixel. The method of removing the moir in the fluoroscopic X-ray image according to this invention includes a moir frequency derivation section 1 that determines frequency of the moir that appears in the fluoroscopic X-ray image, a defective pixel preliminary complement section 2 that forms a preliminary complement image, a moir removal section 3 that conducts frequency analysis of the preliminary complement image to form a moir removed image, an image smoothing section 4 that performs an image smoothing process to the preliminary complement image to form a smoothed image suitable for complement of the defective pixel and a first defective pixel recomplement section 5 that recomplements the defective pixel by superimposing the moir removed image ON the smoothed image.
