PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic apparatus which performs a synthetic aperture method using convergent transmission beam forming and is capable of changing the configuration and process content according to required calculation ability.SOLUTION: The ultrasound diagnostic apparatus comprises: a first phasing addition unit which generates a first acoustic beam signal by performing phasing addition on a sequence of reception signals for a plurality of observation points in a first target region including at least a part of the target region； a parameter calculation unit which calculates a parameter based on the first acoustic beam signal； a second phasing addition unit which generates a subframe acoustic beam signal by performing phasing addition on a sequence of reception signals based on the parameter for a plurality of observation points in a second target region that is the whole or a part of the target region； a synthesizing unit which generates a frame acoustic beam signal by synthesizing the subframe acoustic beam signals； a control unit which determines whether an ultrasound image is generated based on one of the first acoustic beam signal and the frame acoustic beam signal； and an ultrasound image generation unit which generates the ultrasound image.SELECTED DRAWING: Figure 24【課題】集束型の送信ビームフォーミングを用いた合成開口法を行う超音波診断装置であって、必要な演算能力に応じて構成及び処理内容を変更することのできる超音波診断装置を提供する。【解決手段】少なくとも対象領域の一部を含む第１対象領域内の複数の観測点について、受信信号列を整相加算し第１音響線信号を生成する第１整相加算部と、第１音響線信号に基づいてパラメータを算出するパラメータ算出部と、対象領域の全部または一部である第２対象領域内の複数の観測点について、パラメータに基づき、受信信号列を整相加算しサブフレーム音響線信号を生成する第２整相加算部と、サブフレーム音響線信号を合成してフレーム音響線信号を生成する合成部と、第１音響線信号とフレーム音響線信号のいずれに基づいて超音波画像を生成するかを決定する制御部と、超音波画像を生成する超音波画像生成部とを備える超音波診断装置。【選択図】図２４
