An X-ray mammography system including an X-ray detecting unit and an X-ray generating unit. The X-ray detecting unit includes a detecting portion that detects X-rays that have passed through a breast. The X-ray generating unit includes a transmission type target and an electron emitting source and is configured to radiate X-rays toward the detecting portion when irradiated with electrons. The transmission type target has a target layer having an electron incidence surface. The distance between a normal to the target layer and a distal end, which is an end of an X-ray irradiated region of the detecting portion closer to the chest of the testee, is larger than the distance between the normal and a proximal end, which is an end of the X-ray irradiated region far away from the chest.
