A gas processing apparatus of an embodiment includes a gas processing unit, a flow forming unit, an AC power supply, and first and second filters. The gas processing unit includes a plurality of stacks each having a dielectric substrate, a first to a third electrode. The flow forming unit forms a flow of a target gas flowing toward the gas processing unit. The AC power supply applies an AC voltage across the first, second electrodes and the third electrode so as to generate plasma induced flows of the target gas between the dielectric substrates. The first filter is disposed at an upstream of the gas processing unit, and removes ozone. The second filter is disposed at a downstream of the gas processing unit, and removes ozone.
