Ultrasonic diagnostic apparatus of the present invention, certain signal waveforms between adjacent and one period of the specified signal waveform between the one period of the specific signal waveform between the bio-signal capturing multiple cycles sequentially biological signals from the biological signal acquiring unit were evaluated for stability of cardiac function with one cycle of, is selected as the inspection interval cardiac function one cycle specific signal waveforms between adjacent and said one period of said specific signal waveform between based on the content of the evaluation, the selection I include a bio-signal analysis unit to be associated with the time phase of the biological signal the inspection interval that is.本発明の超音波診断装置は、生体信号取得部からの生体信号を順次複数周期取り込んで前記生体信号の特定信号波形間の一周期と前記特定信号波形間の一周期と隣り合う特定信号波形間の一周期との心機能の安定性について評価し、その評価内容に基づき前記特定信号波形間の一周期と前記隣り合う特定信号波形間の一周期を心機能の検査区間として選択し、前記選択された検査区間を前記生体信号の時相に対応付ける生体信号解析部を備える。
