Abstract: An electron-emitting device has a primary and a secondary coil wound on an I-core, an E-core combined with the I-core and a single output terminal extended from one end of the secondary coil. An electron-emitting electrode includes a stainless steel pipe, an insulator-coated conductor inserted in a pipe, and tourmaline powder filling the gap between the pipe and the conductor. The stainless steel pipe is enclosed in a polyethylene pipe, and the openings of the stainless steel pipe and polyethylene pipe are sealed by silicon resin. The electron-emitting electrode is connected to the output terminal of the electron-emitting device and is submerged in an object to be processed, which is in turn charged negatively and activated by high electrostatic potential.