It is possible to allow image processing on a radiation image such that the same effect of scattered radiation elimination as when imaging is actually performed using a grid is obtained. When performing processing for eliminating scattered radiation included in radiation transmitted through a subject M on a radiation image imaged by irradiating the subject M with radiation, a characteristic acquisition unit 32 acquires a virtual grid characteristic as a characteristic of a virtual grid assumed to be used to eliminate scattered radiation at the time of imaging of the radiation image. A scattered radiation elimination unit 36 performs scattered radiation elimination processing of the radiation image based on the virtual grid characteristic.