PROBLEM TO BE SOLVED: To provide a blood purification device capable of detecting blocking of a flow passage without newly providing sensors separately.SOLUTION: A blood purification device includes: control means 13 capable of performing a negative pressure detection process in which an ultrasonic wave is oscillated from an ultrasonic vibration element A3 of bubble detection means 10 in a state that there is no circulation of fluid in a flow passage held by holding means H, and the ultrasonic wave is received by an ultrasonic reception element A4； and negative pressure detection means 14 capable of detecting negative pressure in the flow passage held by the holding means H or a flow passage communicated with the above flow passage based on the ultrasonic wave received by the ultrasonic reception element A4 in the negative pressure detection process.SELECTED DRAWING: Figure 1【課題】別途新たにセンサ類を設けることなく流路の閉塞を検出することができる血液浄化装置を提供する。【解決手段】挟持手段Ｈで挟持された流路に液体の流動がない状態で気泡検出手段１０の超音波振動素子Ａ３から超音波を発振させてその超音波を超音波受信素子Ａ４にて受信させる陰圧検出工程を行わせ得る制御手段１３と、陰圧検出工程において超音波受信素子Ａ４で受信した超音波に基づき挟持手段Ｈで挟持された流路又はその連通した流路の陰圧を検出し得る陰圧検出手段１４とを具備したものである。【選択図】図１
