Provided is a technology capable of obtaining at high speed a three-dimensional image having good image quality, without increasing the load on an ultrasonic diagnostic device. A plurality of filter processing having different effects are performed, prior to rendering, on tomographic volume data that has completed coordinate transformation, and volume data is obtained for each. A prescribed weight is added to each voxel for each of the obtained volume data, and a three-dimensional image is generated from the volume data obtained thereby. The filter processing having different effects may be different types of filter processing such as smoothing and sharpening, the same filter processing but having different strengths, or a combination of filter processing and no filter processing.
