A region-of-interest setting unit sets a region of interest to be included in an ultrasound image. A first movement-amount calculating unit sequentially calculates a movement amount of the set region of interest between reception data along the time sequence as a first movement amount. A transmitting-receiving delay-amount computing unit computes a delay amount for sequentially shifting a scan region of an ultrasonic beam based on the sequentially calculated first movement amount. A computation/control circuit performs control so as to generate a high voltage pulse based on the computed delay amount. A second movement-amount calculating unit sequentially calculates a movement amount of the region of interest between image data along the time sequence as a second movement amount. A display-position correcting unit performs a correction such that the region of interest included in the image data is to be displayed at the same display position, based on the second movement amount.