PURPOSE: To provide a cannula capable of bending only the front end adequate for an auxiliary circulation pump in arbitrary directions.

CONSTITUTION: The front end of the cannula is formed of a soft pipe part 3 and the operator side thereof is constituted of a hard pipe part 4. The cannula is constructed by providing ≥3 pieces of celom pipes 5 at nearly equal interval within the pipe wall, passing yarn 6 for operation into these celom pipes, fixing one end thereof to a annular plate 2 at the front end and leading the other end out of the operator side 7. Only the front end is bent to the yarn side by pulling the yarn.