A turbo blood pump includes a housing 1 having a pump chamber 2, an inlet port 3, and an outlet port 4, an impeller 5 disposed rotatably in the pump chamber, an upper bearing 9 and a lower bearing 10 supporting the impeller rotatably, and a driving force transmitting unit for driving the impeller to rotate. The upper bearing is supported at a position in the pump chamber below the inlet port, so that a cross-sectional area of the pump chamber in a plane including an upper end of the upper bearing and being orthogonal to a shaft of the impeller is larger than a cross-sectional area of a flow path of the inlet port at a portion where the inlet port is coupled to the pump chamber, and thus obstruction with respect to blood flow by the upper bearing is of such a degree as to be permissible from a practical viewpoint, while an impeller is supported by upper and lower bearings. Thereby, the pump is less likely to cause problems of blood stagnation and thrombus formation.