PROBLEM TO BE SOLVED: To provide an artificial lung capable of removing bubbles generated during the extracorporeal circulation without fail.SOLUTION: An artificial lung 10 includes: a housing 2A； a hollow fiber membrane bundle that is stored inside the housing 2A and that is formed by accumulating a large number of hollow fiber membranes having gas exchange function； and a gas inflow part and a gas outflow part that are provided on the upstream side and the downstream side of a gas passage, which is a lumen of each hollow fiber membranes respectively. The gas outflow part includes a first chamber 221a as an airtightly sealed gas outflow chamber that communicates with the gas passage and where gas G flowing down the gas passage flows out, and a pressure adjustment part 5 that adjusts the pressure inside the first chamber 221a.SELECTED DRAWING: Figure 4【課題】体外循環中に生じた気泡を確実に除去することができる人工肺を提供すること。【解決手段】人工肺１０は、ハウジング２Ａと、ハウジング２Ａ内に収納され、ガス交換機能を有する中空糸膜が多数本集積された中空糸膜束と、各中空糸膜の内腔をガス流路として、ガス流路の上流側および下流側にそれぞれ設けられたガス流入部およびガス流出部とを備える。ガス流出部は、ガス流路に連通し、ガス流路を流下したガスＧが流出する、気密的に封止されたガス流出室としての第１の部屋２２１ａと、第１の部屋２２１ａ内の圧力を調整する圧力調整部５とを有する。【選択図】図４
