A plasma reactor for abating hazardous materials included in process gases while being installed on an exhaust path of the process gases toward a vacuum pump is provided. The plasma reactor includes an insulator having a pipe shape through which process gases pass, a first ground electrode connected to a front end of the insulator facing the process chamber, a second ground electrode connected to a rear end of the insulator and provided with a facing part that faces a center of the inside of the insulator along the moving direction of process gases, and a driving electrode fixed to an external circumferential surface of the insulator and connected to a power supply applying an AC or RF voltage.