Plasma generation device and plasma irradiation method

Atmospheric-pressure plasma generation device of the present invention includes heat sinks. Flow paths are formed in the heat sinks, and cooling gas flows in the flow paths, thereby cooling lower housing in which a reaction chamber is formed. Here, the gas used for cooling is warmed by the heat of the lower housing. The warmed gas is supplied into heated gas supply device and heated by heater. The heated gas flows in lower cover and is emitted together with plasma gas from lower cover toward a processing object. Consequently, it is possible to perform cooling of the lower housing heated by electric discharge and perform heating of the processing object, and it is possible to reduce energy required for heating gas.