Abstract: A blood circulation assisting device using a continuous flow blood pump (1) for blood feeding assistance to remove blood through a blood removing pipe (2) and drive out blood at a predetermined flow rate through a blood feeding pipe (3). The blood circulation assisting device includes a current measuring unit (7) for measuring current flowing through a motor (4) driving the pump (1) in order to use the current as data corresponding to a blood flow rate through the continuous flow blood pump (1) and an amplitude detection unit (8) for detecting, from an output of the current measuring unit (7), the amplitude of fluctuation of current flowing through the motor (4) in order to use the amplitude as data corresponding to a flow rate amplitude due to flow rate fluctuation. The amplitude of this fluctuation is divided by an average current value and output as an amplitude index.