Provided is an artificial airway and a breathing circuit provided with the artificial airway, including a tubular outer shell； a moisture permeable and water resistant film disposed on an entire circumference of an internal surface of the outer shell, forming a water retention region with the outer shell, and forming an aeration region on an internal surface side thereof； a feed water inlet provided in the outer shell to supply water to the water retention region； and a heater disposed outside the outer shell, heating the water in the water retention region to generate water vapor, and also heating an inspiratory gas flowing in the aeration region, wherein the water supplied from the feed water inlet is retained in the water retention region by the moisture permeable and water resistant film, and only the water vapor generated by the heating of the heater passes through the moisture permeable and water resistant film and flows into the aeration region to heat and humidify the inspiratory gas flowing in the aeration region.
