To provide a high speed gas carburizing treatment device with an extremely simple structure where the amount of carburizing gas to be used can be saved, and cost can be reduced, and to provide a treatment method therefor.

The gas carburizing treatment device is provided with: a work supporting tool 1; a vessel 2 having dimensions slightly larger than those of a work W, and in which the work supporting tool 1 is arranged at the inside together with the work W; a vessel supporting tool 3 supporting the vessel 2; a gas introducing port introducing carburizing gas inside the vessel 2; an exhaust port 2a exhausting the carburizing gas from the vessel 2 toward the outside; and a rapid heating means 4 arranged at the outside of the vessel 2 and performing heating from the outside of the vessel 2. In this case, the vessel 2 and the rapid heating means 4 are the combination in which the rapid heating means 4 hardly heats the vessel 2.