To improve image quality.SOLUTION: An ultrasound diagnostic device in an embodiment includes a transmission opening synthesis part, a calculation part, and a signal processing part. The transmission opening synthesis part performs transmission opening synthesis for performing coherent addition of a plurality of received signals on the same scan line, having each different transmission opening. The calculation part evaluates coincidence of each phase of the plurality of received signals, and calculates an evaluation value at each observation point. The signal processing part evaluates coincidence of each phase of the plurality of received signals, and calculates the evaluation value at each observation point.SELECTED DRAWING: Figure 1【課題】画質を向上させること。【解決手段】実施形態の超音波診断装置は、送信開口合成部と、算出部と、信号加工部とを備える。送信開口合成部は、送信開口が異なり、同一走査線における複数の受信信号をコヒーレント加算する送信開口合成を行う。算出部は、前記複数の受信信号の位相の一致度を評価して観測点ごとに評価値を算出する。信号加工部は、前記複数の受信信号の位相の一致度を評価して観測点ごとに評価値を算出する。【選択図】図１
