Gas concentration in the soil air is different from that in atmosphere, because it is affected by activity of microorganisms, gas diffusion and chemical reaction. Under the field condition for cultivation, large changes in soil physical properties by human operations may affect the gas behavior in the soil. The objective of this study is to clear gases behaviors in the soil from field measurements, column experiments and simulations. Under field condition, CO2 and O2 gas concentrations in the deeper layer than the hard pan changed remarkably with seasons, whereas those concentrations in the top layer changed little. From the column experiments, CO2 gas concentrations in the top layer increased with infiltration, whereas CO2 gas concentrations decreased both in the other layers and in the atmosphere. The changes of O2 gas concentrations after infiltrations are opposite to those of CO2 gas. Simulation with measured gas CO2 gas concentration of column experiment suggested that the activity of microorganisms at the hard pan might be larger, and also, prevention of gas movement above the hard pan or large flux of gas through the top layer might be keep CO2 gas concentration low in the top layer. It was concluded that gas concentrations changes above and below the hard pan, because the hard pan affects the activity of microorganisms and gas diffusion.