To improve the accuracy in analyzing an X-ray image acquired in pre-mammography.

The mammographic system includes: an X-ray source for emitting X rays; an X-ray detector with two-dimensionally disposed sensing elements, which generate electric signals according to the emitted X rays, for reading the electric signals generated by the sensing elements as image signals; and a control part for determining conditions for reading the image signals by the X-ray detector in main mammography and in the pre-mammography performed ahead of the main mammography. The control part determines a larger reading gain of the image signals in the pre-mammography than in the main mammography (a step P1).