A centrifugal fluid pump assembly includes a centrifugal fluid pump and a control device. The centrifugal fluid pump comprises a pump section including a housing and an impeller having a first magnetic material and a second magnetic material and accommodated for rotation in the housing and without contacting the housing, an impeller rotational torque generating section including a rotor having a magnet for attracting the first magnetic material of the impeller and a motor for rotating the rotor, and an impeller position control section having an electromagnet for attracting the second magnetic material of the impeller. The control device has a function of limiting an input of a number of rotations of the motor more than a predetermined number of rotations or limiting an input of a motor-driving current having a value more than a predetermined value.