PROBLEM TO BE SOLVED: To surely lead exhalation of a subject to an exhalation density detection sensor, regardless of a shape of his/her face, differing by each subject.SOLUTION: A mask 1 worn on the face of a subject covers at least part of the nose and mouth of the subject, and includes a wall part 2 partitioning an interior space 2b. An exhalation introduction part 3 is arranged in the interior space 2b, and introduces exhalation of the subject. A ventilation part 4 partitions a ventilation path for introducing exhalation of the subject, introduced from the exhalation introduction part 3 to an exhalation density detection sensor. The exhalation introduction part 3 is adjustable in its position in the interior space 2b.COPYRIGHT: (C)2015,JPO&INPIT【課題】被検者ごとに異なる顔面の形状によらず、被検者の呼気を確実に呼気濃度検出センサに導く。【解決手段】被検者の顔面に装着されるマスク1は、被検者の鼻と口の少なくとも一部を覆い、内部空間2bを区画する壁部2を備える。呼気導入部3は、内部空間2bに配置され、被検者の呼気を導入する。通気部4は、呼気導入部3より導入された被検者の呼気を呼気ガス濃度検出センサに導く通気路を区画する。呼気導入部3は、内部空間2bにおける位置が可変とされている。【選択図】図2