An ultrasonic imaging apparatus includes an image data production device for producing image data composed of a plurality of frame image data items acquired successively from the subject during a scan time, a continuous time field image data production device for producing continuous time field image data from the image data by adding up the plurality of frame image data items acquired successively during the scan time, a time-sequential change process image data production device for producing time-sequential change process image data, and a synthesis/output device for synthesizing an image represented by the continuous time field image data and each of the images represented by the time-sequential change process image data by superimposing the image represented by the continuous time field image data on each of the images represented by the time-sequential change process image data.