Abstract: There is disclosed a plasma gun for bio/medical treatment using atmospheric plasma. The disclosed plasma gun comprises a housing having an elongate chamber provided therein, the chamber having an end at which a nozzle for spraying plasma is positioned; a gas supply unit for supplying a reaction gas to the chamber; and a plasma discharge unit formed with an elongate cavity communicating with the nozzle, the plasma discharge unit including first and second electrodes and a dielectric or insulating barrier material for plasma ignition in the elongate cavity.