A centrifugal blood pump apparatus includes an impeller (10) provided in a blood chamber (7), a permanent magnet (15) provided in one surface of the impeller (10), a permanent magnet (16) provided in an inner wall of the blood chamber (7), a permanent magnet (17) provided in the other surface of the impeller (10), and a magnetic material (18) and a coil (20) provided in a motor chamber (8) for driving the impeller (10) to rotate via a diaphragm (6). Grooves for hydrodynamic bearing(21, 22) are formed in the diaphragm (6) facing the impeller (10), and in the inner wall of the blood chamber (7), respectively. As a result, the impeller (10) can be smoothly activated to drive by controlling a coil current.
