A gas oven configured to use a single cooking cavity being divided into a plurality of individual cooking cavities by mounting a divider at the cooking space. The gas oven includes a forced air supplying device capable of forcedly supplying air to the individual cooking space at an upper portion of the cooking space, and a natural air discharging device capable of naturally discharging waste air of the individual cooking space at a lower portion of the cooking space, when each individual cooking space is shut off by the divider.