PROBLEM TO BE SOLVED: To provide a radiographic apparatus for acquiring an accurate gain image using an image captured by automatically detecting the start of irradiation of radioactive rays.SOLUTION: A radiographic apparatus for detecting a start of irradiation of radioactive rays on the basis of a radiation dose detected by a radiation detector and performing radiation image capturing using the radiation detector performs image capturing by irradiation of radioactive rays in a state in which a subject is not present, and acquires a plurality of base images (S211), identifies an artifact area resulting from a time difference from the start of the actual irradiation of radioactive rays to the detection of the start of irradiation for the plurality of the acquired base images (S221), and creates a gain image for gain correction by synthesizing the plurality of base images without using image information on the identified artifact area (S223).SELECTED DRAWING: Figure 2B
