The ventricular assist device 110 of the present invention includes a rotating portion 10, a base 20, and a housing 30, and the value obtained by dividing the external volume of the rotating portion 10 by the rotating volume of the rotating portion 10 is 0.1 to 0.4. Is within the range of. Further, in the ventricular assist device 110 of the present invention, when the volume of the pump chamber 31 divided by the predetermined plane P on the side where the rotating portion 10 exists is set as the main volume of the pump chamber, the rotating volume of the rotating portion 10 Is divided by the main volume of the pump chamber and is in the range of 0.4 to 0.7. Further, in the ventricular assist device 110 of the present invention, the value obtained by dividing the external volume of the rotating portion 10 by the main volume of the pump chamber is in the range of 0.05 to 0.2. According to the ventricular assist device 110 of the present invention, the pressure loss can be sufficiently reduced and the pump can be used at a high flow rate. As a result, it is possible to suppress the degree of deterioration of the user's health condition when used for a long period of time as compared with the conventional ventricular assist device pump.本発明の補助人工心臓ポンプ１１０は、回転部１０と、基部２０と、ハウジング３０とを備え、回転部１０の外形体積を回転部１０の回転体積で割った数値が０．１～０．４の範囲内にある。また、本発明の補助人工心臓ポンプ１１０は、所定の平面Ｐで区分したポンプ室３１の容積のうち回転部１０が存在する側の容積をポンプ室主要容積とするとき、回転部１０の回転体積をポンプ室主要容積で割った数値が０．４～０．７の範囲内にある。さらに、本発明の補助人工心臓ポンプ１１０は、回転部１０の外形体積をポンプ室主要容積で割った数値が０．０５～０．２の範囲内にある。 本発明の補助人工心臓ポンプ１１０によれば、圧力損失を十分に減らして高流量での使用が可能となる。その結果、従来の補助人工心臓ポンプと比較して、長期間使用したときに使用者の健康状態が悪化する度合いを抑制することが可能となる。
