Aliphatic amine compounds have very low detectable threshold value concentrations, and especially trimethyl amine is one of the main odor-active compounds in atmospheric environment. Concentration of a large amount (10~100 L) of air sample was needed to detect trace amounts of amine compounds by GC/FTD. Amine compounds in ambient air were absorbed in sulfuric acid solution by using impingers and sampling pump. Some amount of the absorption solution was injected in bubbling bottle which a concentration tube was connected with, and that amine gas which was isolated from bubbling bottle was trapped in a concentration tube dipped in liquid argon under a constant helium flow. A concentration tube was disjoined from the bubbling bottle and was connected to injection port of gas chromatograph. Amine compounds trapped in a concentration tube was introduced into the packed column by thermal desorption after flow rate of carrier gas and detector signal had been stabilized enough. Sampling volume of ambient air was different from place to place in the range of 10~100 L, and flow rate through impingers was 5 L/min. Atmospheric concentrations of trimethyl amine were below 16.0 ppbv in the boundary of business establishment and below 420.0 ppbv at the gas releasing port of business establishment in the industrial area.