According to one embodiment, an ultrasonic diagnostic device includes a first rendering unit, a second rendering unit, a superimposition processing unit, a display control unit. The first rendering unit generates a first rendering image according to a first rendering method based on volume data collected by three-dimensionally scanning a subject with ultrasonic waves. The second rendering unit generates a second rendering image according to a second rendering method that is different from the first rendering method, based on the volume data. The superimposition processing unit generates a superimposed image in which at least a part of the first rendering image and a part of the second rendering image are superimposed on each other. The display control unit causes a display device to display the superimposed image. The superimposition processing unit adjusts a superimposition ratio of the first and second rendering images in the superimposed image.