An ashing device and ashing method that can positively remove resist from a wafer while preventing degradation of the film material properties of exposed porous Low-K film on the wafer. The ashing device of the present invention introduces a gas to a dielectric plasma generating chamber 14, excites said gas to generate a plasma, and performs plasma processing using said gas plasma on a processing work S in use of a Low-K film. The ashing gas introduced from a gas regulator 20 is an inert gas to which H2 has been added. The configuration is formed so that plasma is generated from the gas blend, and the resist is removed by the hydrogen radicals generated.