PURPOSE: To improve performance and efficiency of denitration/dedusting in all operation range from the starting to a full load operation in an electric discharge denitration/dedusting device for private power generation equipment.

CONSTITUTION: Exhaust gas from a diesel engine 5 which drives a diesel generator 6 is purified by a plurality of electric discharge pipe modules 11 to 16. Sensors 71, 72 are arranged on upstream and downstream sides of the modules 11 to 16. Voltage application and frequency are adjusted in every module according to detecting rates, for varying performance of denitration and dedusting. It is thus possible to operate an electric discharge denitration/dedusting device which dispenses with NH3 gas and has excellent stability and handlability with high performance and efficiency in all operation range. Problem such as increasing of power consumption at the starting time is solved.