| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas concentration measuring device which causes no problem in measuring a gas concentration even in the case that vibration of each of a plurality of mirrors creates a slight change in an installation angle when a predetermined gas concentration is measured while a laser beam is reflected by the plurality of mirrors.SOLUTION: A plurality of mirrors installed to surround a region to be measured include: a plurality of mirrors sequentially reflecting a laser beam emitted by laser emitting means; a retroreflection body such as a retroreflector which causes the laser beam reflected by the n-th mirror which reflects the laser beam at n-th time to reflect at an emitting point of the laser beam in the n-th mirror; light quantity measuring means for measuring a light quantity of the laser beam which is reflected by the plurality of mirrors and the retroreflection body to be again reflected and returned to the plurality of mirrors; and computing means for computing a predetermined gas concentration in the region to be measured on the basis of the light quantity measured by the light quantity measuring means. |
