The widespread raising of swine in farms becomes a serious problem in terms of the emission of carbon dioxide (CO₂) and methane (CH₄). This study aims to measure concentrations of carbon dioxide and methane, which account for the largest percentage of carbon emissions, to temporally estimate the carbon emitted during the pig-manure composting process. The research subject was a farmhouse raising 3000 growing pigs and 100 mother pigs. The capacity of the composting facility for pig manure treatment was 330 m², and the daily treatment was about 6 tons. After the pig manure discharged from the pig farm was delivered to the composting facility, for the 8 days including 6 before mixing and 2 after mixing, the concentrations of CO₂ and CH₄ were measured. The result shows that the CO₂ and CH₄ concentrations in the composting facility were 1208 ± 385 ppm and 95 ± 10 ppm, respectively. In the comparison of concentrations before and after mixing at the composting facility, the values of both CO₂ and CH₄ increased, and the temperature increased as well. The concentration of CO₂ and CH₄ increased to 499 ± 103 ppm and 3 ± 11 ppm, respectively, and the temperature rose by 3.7 ± 1.0 °C and 1.6 ± 2.4 °C, respectively. In the correlation analysis (r = 0, p < 0.05), the carbon dioxide emission in the composting process was 15.564 ± 3.671 tons C/year, whereas carbon emission was 1.379 ± 0.147 tons C/year. The concentrations of CO₂ and methane, which are the current major atmospheric pollution sources, were respectively analyzed during the pig-manure composting process in this study to understand their effects. Thus, this paper attempts to elucidate the carbon cycle by measuring and analyzing the carbon data obtained from livestock excretions to secure a supply chain based on the intelligent use of the data.