In this study, a device and methodology has been proposed for analysis of O_2 and CO_2 by the Gas-Chromatography which in widely used in the field of applied chemistry. In order to determine whether the Gas-Chromatography is reliable or not, comparison between oxygen uptake determined by Gas-Chromatography and that by Scholander gas analyzer was performed. It was found that there was a close correlation between the both methods (r = 0.997). Furthermore, no significant differences were observed between the values obtained by two methods.