In centrifugal pumps 10, 30, 60, 70, and 80 having a rotating centrifugal impeller 14, the flow rate and head of the pumps are estimated on the basis of transverse force applied to the centrifugal impeller 14 during rotation of the centrifugal impeller 14, and evaluation is also made for a circulatory state of the pulsating cardiovascular system. Thereby, it is possible to measure the flow rate and head of the centrifugal pumps and evaluate circulation functions during circulatory assistance by the centrifugal pump.