An ultrasonic diagnostic apparatus and program

And suppressing a decrease in frame rate provides an ultrasonic diagnostic apparatus and program capable of improving the resolution. Control unit 18, each time the image data for each frame is generated, determines whether or not a still image based on the image data of two or more frames. Then, the control unit 18, when it is determined that the still image, at least, by synthesizing the image data of two consecutive frames to generate a composite image data. Then, the control unit 18, when not determined that the still image, from the data of one frame image of two consecutive frames, for placement between pixels adjacent in the image data of the one the pixel data, generated based on at least one of the pixel data of the pixel to be the next, by synthesizing the pixel data and the one of the image data thus generated to generate combined image data.