The mammographic apparatus of this invention maintains peripheral portions of the breast area Ma of the sternal plate of a patient M in contact with a sternal plate contact box 3 during radiography for RI distribution images of the breast area Ma of the patient M. Since the body motion accompanying respiration of the patient M shifts from the breast side to the back side, the motion of the breast area Ma of the patient M accompanying respiration of the patient M is suppressed easily. In addition, since radiography for RI distribution images is carried out with the patient M in a seated position seated on a seating unit 2, the apparatus is compact and can installed in a limited area, compared with an apparatus that carries out radiography for RI distribution images with a patient in a sleeping position lying on her back or on a side on a top board.