According to one embodiment, a medical image diagnostic apparatus comprises a position acquisition unit, a data acquisition unit, an alignment unit, a decision unit, and a data generation unit. The position acquisition unit acquires the position of a medical tool in an imaging region with respect to the imaging region at the time of obtaining the medical image. The data acquisition unit acquires volume data corresponding to a three-dimensional region including the imaging region. The alignment unit decides the position of the volume data. The decision unit decides the position of the medical tool with respect to the volume data based on the position of the medical tool and the position of the volume data. The data generation unit generates support volume data by adding support information indicating the position of the medical tool to the volume data.
