PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic apparatus in which the signal acquisition time resolution and/or spatial resolution for ultrasound elastic modulus measurement is improved.SOLUTION: A reception beam former unit 108 comprises: a plurality of sub-phasing addition parts 1083 which generate an acoustic line signal by phasing and adding, for each of a plurality of sub-transducer arrays 101ao obtained by dividing a transducer array constituted of a plurality of transducers 101a into array direction, receive-wave signal trains rfk based on reflection waves received from a subject by each transducer contained in each of the plurality of sub-transducer arrays 101ao at a plurality of measurement points located in a subject depth direction of the sub-transducer array 101ao in a detection wave radiation region, and which then generate acoustic line signal sub-frame data corresponding to each of the plurality of sub-transducer arrays 101ao； and a main addition part 1084 which generates acoustic line signal frame data by adding generated plural acoustic line signal sub-frame data sets, using the positions of measurement points as reference.SELECTED DRAWING: Figure 7【課題】超音波弾性率計測の信号取得時間分解能又は/及び空間分解能とを改善した超音波診断装置を提供する。【解決手段】受信ビームフォーマ部１０８は、複数の振動子１０１ａからなる振動子列を列方向に分割した複数の部分振動子列１０１ａｏの各々について、検出波照射領域における各部分振動子列１０１ａｏの被検体深さ方向に位置する複数の観測点についてその部分振動子列１０１ａｏに含まれる振動子各々が被検体から受波した反射波に基づく受波信号列ｒｆｋを整相加算することにより音響線信号を生成して、複数の部分振動子列１０１ａｏの各々に対応する音響線信号サブフレームデータを生成する複数のサブ整相加算部１０８３と、生成された複数の音響線信号サブフレームデータを観測点の位置を基準に加算して音響線信号フレームデータを生成する主加算部１０８４とを備えた。【選択図】図７
