System of the present invention provides a kind of Supersonic waves gas concentration measuring device, it is to include in the piping of what sample gas circulation relatively to ground configuration and transmission and two ultrasonic vibrators, temperature-sensitive sticker and the pressure sensor person that receive ultrasonic, and the Supersonic waves gas concentration measuring device, system includes one to the spread speed correction factor according to corresponding what pressure, and calculate the mechanism of sample gas concentration, also, system of the present invention provides, a kind of no matter the pressure of sample gas all can measure the method and device of correct gas concentration.本發明係提供一種超音波式氣體濃度測定裝置，其係包含有於樣品氣體流通的配管中相對向地配置且發送及接收超音波之二個超音波振動器、溫度感測器及壓力感測器者，且該超音波式氣體濃度測定裝置，係包含有一用以依對應於壓力之傳播速度修正係數，而演算樣品氣體濃度之機構，又，本發明係提供一種無論樣品氣體之壓力都可測量正確的氣體濃度之方法及裝置。
