A sample moves, either naturally (as in the case of the heart) or by application of force, and its movement is measured. A processing unit calculates first displacement related information concerning a first direction of the object to be measured (the sample) by using data in either one of an increase period and a decrease period of the force applied to the objected to be measured, from data received by a first ultrasonic probe. In addition, the processing unit calculates second displacement related information concerning a second direction of the object to be measured by using data in the same period as that used to calculate the first displacement related information, from data received by a second ultrasonic probe.
