Most of methane gas result from waste matter in landfill, therefore the persons concerned take an increasing interest in management of gases in landfill. Infrared Gas Analyzer was used to measure components of gases, CH4, CO2, O2, through gas exhausted pipe. To measure amount of the gas flow meter(Portable Hot-Line Current Meter) was used and it was set at right angles with direction of the flow. In this research the total amount of methane gas produced in Beck-Suk Landfill was calculated through FOD method suggested by IPCC. This research found that in Chon-An Beck-Suk Landfill anaerobic resolution was made actively and the amount of methane gas produced there was 54.14%, which is higher than common figure, 50%, in other researches. The components of reclaimed waste matter, especially, organic waste matter can have a great effect of the amount of the greenhouse gases produced in landfill. We can expect that the amount of greenhouse gas will decrease from 2005, when it will be prohibited from carrying kitchen refuse and sludge into landfill.