Employing automatic analysis software, GTms-1 series can measure gas transmission rate of high-barrier films used for such flexible devices as organic EL panel or electronic paper. System uses Standard Conductance Unit to offer absolutely corrected measurement data. Minimum measurement sensitivity is 10-6g /m²/day or less for water vapor and 10-2cc/ m²/day or less for oxygen. Via use of mass spectrometer, other gases, such as O2 or N2, as well as water vapor are available.