According to one embodiment, a mammography apparatus includes an X-ray, an imaging stage, a pressing plate, a guide information generator, and an X-ray detection unit. The X-ray tube generates X-rays. The imaging stage supports a breast. The pressing plate presses the breast supported on the imaging stage. The guide information generator provides the imaging stage with guide information for guiding a placement position of the breast. The guide information is generated based on a nipple position, an image start position, and an image end position of a previous image of the breast. The X-ray detection unit generates X-ray projection data by detecting X-rays transmitted through the breast by an X-ray detector.
