<；P>；PROBLEM TO BE SOLVED: To provide a compact, centrifugal type pump apparatus smoothly activating an impeller to rotate. <；P>；SOLUTION: The centrifugal type blood pump apparatus is equipped with the impeller 10 provided in a blood chamber 7, a permanent magnet 15 provided on one surface of the impeller 10, a permanent magnet 16 provided on the inner wall of the blood chamber 7, a permanent magnet 17 provided on the other surface of the impeller 10, a magnetic body 18 and a coil 20 provided in a motor chamber 8 for driving the impeller 10 to rotate through a partition wall 6, and a comparison operation part 31 for obtaining a position of the impeller 10 from information indicating a coil voltage, a coil current, and the number of revolutions of the impeller 10. Dynamic pressure grooves 21, 22 are respectively formed on the partition wall 6 facing the impeller 10 and the inner wall of the blood chamber 7. Consequently, the impeller 10 is smoothly activated to rotate by controlling the coil current. <；P>；COPYRIGHT: (C)2010,JPO&INPIT
