A medical image diagnostic apparatus provided with an image acquisition unit configured to acquire in-vivo information about an object to be examined as a medical image, a display unit configured to display the medical image, a setting unit configured to set a target region of volume measurement in the medial image displayed on the display unit, a calculation unit configured to perform calculation to split the target region into a plurality of volume elements, calculate the moving distance of the vertices of the volume elements when the target region of the acquired medical image moves, calculate the volumes of the volume elements after the movement using the calculated moving distance of the vertices, totalizing the calculated volumes of the volume elements after the movement and using the total volume as the volume of the target region, and a control unit configured to display the volume of the target region on the display unit.
