Provided is an ultrasound diagnostic apparatus capable of creating a three-dimensional image that expresses the shading effect due to leakage, absorption or others of light. The apparatus displays a three-dimensional image of an object based on luminance volume data, and includes: a light source information setting unit configured to set light source data indicating a property of a light source that is set in a three-dimensional space an optical property setting unit configured to set a weight coefficient indicating an optical property of the luminance volume data with respect to the light source an illuminance calculation unit configured to calculate an illuminance at a position corresponding to a coordinate of the luminance volume data, based on the optical data and the weight coefficient, and to create illuminance volume data based on the calculated illuminance and a volume rendering unit configured to create the three-dimensional image from the data.
