According to embodiments, in a medical diagnostic imaging apparatus, an imaging unit captures a subject in a second X-ray irradiation area narrower than a first X-ray irradiation area. An X-ray image generating unit generates a first X-ray image in the first X-ray irradiation area and a second X-ray image in the second X-ray irradiation area based on an imaging result by the imaging unit. The adjusting unit calculates a statistic of a pixel value of the first X-ray image and adjusts an operating condition of the imaging unit so that the statistic approaches a threshold. A control unit causes the imaging unit and the X-ray image generating unit to generate the X-ray image based on the adjusted operating condition. Subsequently, the control unit performs control for causing the imaging unit and the X-ray image generating unit to generate the second X-ray image based on the operating condition.
