An ultrasound diagnostic apparatus includes: an ultrasound probe including an capacitive micromachined ultrasound transducer an ultrasound observation apparatus to which the ultrasound probe is detachably connected, the ultrasound observation apparatus including a transmission circuit that generates an ultrasound transmission signal, and a reception circuit a transmission ultrasound transducer and a reception ultrasound transducer included in the capacitive micromachined ultrasound transducer, the transmission ultrasound transducer including a plurality of transmission capacitive cells that each send ultrasound out, and the reception ultrasound transducer including a plurality of reception capacitive cells that each receive reflected ultrasound of the sent-out ultrasound and output an ultrasound reception signal a transmission signal cable connecting the transmission ultrasound transducer and the transmission circuit a reception signal cable connecting the reception ultrasound transducer and the reception circuit a first matching section and a second matching section that perform electrical impedance matching for the ultrasound transmission signal and the ultrasound reception signal.超音波診断装置は、静電容量型超音波振動子を有する超音波プローブと、超音波プローブが着脱自在に接続され、超音波送信信号を発生する送信回路と受信回路とを有する超音波観測装置と、静電容量型超音波振動子を構成し、超音波を送出する複数の送信静電容量型セルから構成される送信用超音波振動子及び送出された超音波の反射超音波を受信して超音波受信信号を出力する複数の受信静電容量型セルから構成される受信用超音波振動子と、送信用超音波振動子と送信回路との間を接続する送信信号用ケーブルと、受信用超音波振動子と受信回路との間を接続する受信信号用ケーブルと、超音波送信信号及び超音波受信信号に対する電気的インピーダンスの整合をそれぞれ行う第1及び第2の整合部と、を備える。
