If multiple organizations with different sound velocities in the field of view of the measurement object such as a living body are mixed, to measure the hardness of the viscosity or the elastic modulus with high accuracy. As a means for detecting the non-uniformity of the speed of sound in the tissue of the object, is applied to the ultrasonic probe 1 for generating a displacement from the displacement transmission beam generation beam generating portion 13 of the displacement generator 10, the living tissue is irradiated with focused ultrasound, to generate shear waves. Was detected using the displacement detecting reception beam calculation unit 23 and the displacement detecting transmission beam generator 22 of the displacement detector 20, the displacement time waveform of a plurality of positions shear wave, for example the maximum amplitude value, and the like integrated value of obtaining information of at least two. The non-uniformity detection unit 26 of the displacement detector 20 detects the physical quantity related to non-uniformity of the speed of sound on the basis of the information of the two, due to the tissue structure, and displays it on the display unit 5.生体などの測定対象物の視野内に異なる音速を持つ複数の組織が混在している場合に,高精度に弾性率や粘性等の硬さを測定する。対象物の組織内の音速の不均一性を検出する手段として,変位生成部10の変位生成用ビーム生成部13から変位生成用送波ビームを超音波探触子1に印加し,生体組織内に集束超音波を照射し,ずり波を発生させる。変位検出部20の変位検出用送波ビーム生成部22と変位検出用受波ビーム演算部23を用いて検出した,ずり波の複数の位置の変位時間波形から,例えば積分値と最大振幅値等の少なくとも2つの情報を得る。変位検出部20の不均一性検知部26により,これら2つの情報に基づき,組織構造に起因する音速の不均一性に関する物理量を検出し,表示部5に表示する。
