1. An ultrasonic diagnosing apparatus comprising: an ultrasound probe; a transmitting and receiving device for transmitting an ultrasound wave from the ultrasound probe to within an object to thereby collect ultrasound echo signals from within the object; a power/variance acquiring device for acquiring power and variance at a large number of two-dimensionally distributed sampling points from the ultrasound echo signals; an ultrasonic image generating device for increasing luminance according as pixels corresponding to sampling points high in power, and generating, when there are two sampling points identical in power but different in variance and low in power, an ultrasonic image in which the luminance of the sampling point relatively large in variance is set higher than that of the sampling point relatively small in variance; and an image display device for displaying the ultrasonic image thereon.