An image obtainment unit obtains a radiographic image radiographed by irradiating a subject with radiation. A first information obtainment unit obtains information about at least one of a radiography condition during radiography of the subject, a subject condition and detector characteristics, which are characteristics of the radiation detector. A second information obtainment unit obtains body thickness information representing the body thickness of the subject. A target S/N setting unit sets a target S/N of the radiographic image based on the body thickness information and the information about at least one of the radiography condition, the subject condition and the detector characteristics. An image processing unit corrects the S/N of the radiographic image to the target S/N by performing, on the radiographic image, noise removal processing.
