PURPOSE: To provide a sealing mechanism for an artificial heart, which enables a pump for a main body of the artificial heart to accurately function without maintenance for a prolonged period of time and maintain complete shaft sealing.

CONSTITUTION: A main body of an artificial heart comprises a pump 4 of a cylindrical shape and a driving part 5 installed at the base of the pump 4 and for driving the pump 4 through a driving shaft 10. The driving shaft 10 has a lower portion carried in a kinetic pressure bearing 31 on the side of the driving part 5 and an upper portion carried in a one-way kinetic pressure bearing 11. A chamber 12 for a lubricating liquid is formed between the kinetic pressure bearing 31 and the one-way kinetic pressure bearing 11, such that the driving shaft 10 extends therethrough. The main body of the artificial heart also has a casing 9. A plurality of suction openings 17 are axially formed in a portion of the casing 9 corresponding to the chamber 12 for a lubricating liquid. A filter 13 for hemofiltration covers the suction openings 17.