A first frequency analysis unit performs frequency analysis on a reference radiographic image of plural radiographic images obtained by tomosynthesis imaging using a grid, and obtains a frequency characteristic of a periodic pattern caused by the grid and a frequency analysis result. A second frequency analysis unit performs, based on the frequency analysis result, limited frequency analysis on a radiographic image or images other than the reference radiographic image, and obtains a frequency characteristic of the periodic pattern about the radiographic image or images. A suppression unit performs, based on the frequency characteristic, processing for suppressing the periodic pattern in all of the radiographic images.