An imitating lung device includes a first liquid accommodating layer, a first elastic membrane, an airway layer, a second elastic membrane and a second liquid accommodating layer. A first liquid chamber is formed in an inner surface portion of the first liquid accommodating layer. The airway layer includes a plurality of air channels and a plurality of imitating alveolar regions. The imitating alveolar regions are communicated with the air channels. The air channels simulate a branched structure of the 15th generation to the 19th generation of a human lung, and the imitating alveolar regions simulate a branched structure of the 20th generation to the 23th generation of a human lung. A second liquid chamber is formed in an inner surface portion of the second liquid accommodating layer. |