A centrifugal blood pump apparatus includes an impeller provided in a blood chamber, a permanent magnet provided in one surface of the impeller, a permanent magnet provided in an inner wall of the blood chamber, a permanent magnet provided in the other surface of the impeller, and a magnetic material and a coil provided in a motor chamber for driving the impeller to rotate via a diaphragm. Grooves for hydrodynamic bearing are formed in the diaphragm facing the impeller, and in the inner wall of the blood chamber, respectively. As a result, the impeller can be smoothly activated to drive by controlling a coil current.
