Abstract: This invention provides a processing device allowing a plurality of types of processing including electron beam processing to be carried out on a substance disposed in a processing chamber, and processing methods that use such a processing device and allow prescribed processing to be carried out in an advantageous way, the processing device has a processing chamber provided with a support member, an electron beam source provided in the processing chamber and emits an electron beam toward the substance supported by the support member, and an emission gas supply system provided in the processing chamber and supplies an emission gas that emits UV light upon being subjected to an electron beam, moreover, a low pressure system that reduces the pressure in the processing chamber and a process gas supply system that supplies a process gas are preferably provided in the processing chamber, and in the processing methods, such a processing device is used, and by adjusting the pressure in the processing chamber, electro