An image forming processing unit forms image data for the interior of a body on the basis of a received ultrasonic signal. A Doppler processing unit generates Doppler information for the body interior on the basis of the receiving signals of ultrasonic waves. A velocity vector calculating unit generates velocity information (velocity vector) for blood flow on the basis of the Doppler information for the body interior. A region of interest setting unit sets a region of interest corresponding to a heart cavity in the image data. An energy calculating unit calculates the amount of energy lost in the blood flow in the heart cavity on the basis of the blood flow velocity information in the region of interest corresponding to the heart cavity.
