The ultrasonic diagnostic apparatus sets a specific part in the subject, and pushes the plurality of transducers 101a to transmit the push pulse pp, and the focused region roi is focused outside the region of interest roi in the subject. A detection wave pulse generator 105 for transmitting the detection wave pulse pwi passing therethrough a plurality of times, and generating acoustic line signals for a plurality of observation points Pij in the region of interest roi corresponding to each of the plurality of detection wave pulses pwi. , A displacement detector 109 for detecting the displacement of the tissue in the region of interest roi from the sequence of the acoustic ray signal frame data dsi, and a sequence of wavefront frame data wfi representing the wavefront position of the shear wave, and based on this, the region of interest and a modulus of elasticity calculation unit 110 that calculates the propagation speed of shear waves in the roi or the frame data emk of the modulus of elasticity.超音波診断装置は、被検体中に特定部位を設定し、複数の振動子１０１ａにプッシュパルスｐｐを送信させるプッシュパルス発生部１０４と、被検体中の関心領域ｒｏｉ外に集束し関心領域ｒｏｉを通過する検出波パルスｐｗｉを複数回送信させる検出波パルス発生部１０５と、複数回の検出波パルスｐｗｉの各々に対応して関心領域ｒｏｉ内の複数の観測点Ｐｉｊに対する音響線信号を生成して、音響線信号フレームデータｄｓｉのシーケンスから関心領域ｒｏｉ内の組織の変位を検出する変位検出部１０９と、せん断波の波面位置を表した波面フレームデータｗｆｉのシーケンスを生成し、これに基づき関心領域ｒｏｉ内のせん断波の伝播速度、又は、弾性率のフレームデータｅｍｋを算出する弾性率算出部１１０とを備えた。
