PROBLEM TO BE SOLVED: To provide an oxygenator that combines a heat exchanger, a gas exchanger, an arterial filter, and a filter frame in a single structure.SOLUTION: The oxygenator permits fewer fluid connections and thus may simplify an extracorporeal blood circuit, including an artificial heart-lung machine and a blood reservoir, in which it is used. In some embodiments, the oxygenator may be configured to include multiple purge ports for purging bubbles both before and after filtering the blood.