Disclosed is a high sensitive gas sensor using a carbon material containing an ionized metal catalyst and a method of manufacturing the same. The method includes the steps of: (1) preparing a hydroxide solution by dissolving a hydroxide in a distilled water; (2) dissolving a metal catalyst in the hydroxide solution; (3) immersing the carbon material in a solution obtained through step (2) and stirring the carbon material; (4) heat-treating a mixture obtained through step (3); (5) cleaning the heat-treated carbon material obtained through step (4); (6) drying the carbon material cleaned through step (5); and (7) manufacturing the gas sensor by loading the carbon material obtained through step (6) on a substrate. The gas sensor having high sensitivity and responsiveness with respect to a target gas even in a normal temperature is obtained.