A ventricular assist blood pump of the present invention includes: a rotational part having an impeller and a housing which houses the rotational part therein. In the ventricular assist blood pump, a difference between a maximum flow rate and a minimum flow rate of a liquid in a state where the ventricular assist blood pump is connected to a liquid-discharge source which discharges the liquid while increasing and decreasing the flow rate of the liquid at a fixed cycle is 40% or more of a difference between the maximum flow rate and the minimum flow rate of the liquid in a state where the ventricular assist blood pump is not connected to the liquid-discharge source. A ventricular assist blood pump of the present invention can suppress the degree at which the health of a user deteriorates during long-term use compared to a conventional ventricular assist blood pump.