An existing ultrasonic diagnostic device is used to obtain a color flow image of a target object whose stiffness is to be measured. At this time, a vibration exciter applies a micro vibration with a frequency of n/4 (n represents an odd number equal to or larger than 1) to the target object with respect to a burst frequency of an ultrasonic pulse to generate a shear elastic wave. As a result, a striped pattern corresponding to the stiffness of the target object caused by the shear elastic wave appears on a display of the ultrasonic diagnostic device as a shear elastic wave detection image.
