A particulate matter reducing system installed in an exhaust pipe of an internal combustion engine, the system comprising: a first conductor provided in the form of a tubular body through which a gas stream flows and to which a ground power supply is connected; a second conductor disposed in the first conductor and having an emitter which comes into contact with the gas stream and generates non-thermal plasma; and an insulator configured to electrically separate the second conductor from the first conductor, wherein a predetermined level of direct current voltage is continuously applied to the second conductor by a high voltage applying unit, wherein the direct current voltage is -30 kV to -80 kV,, wherein the second conductor includes a vertical rod disposed in a radial direction of the first conductor; a horizontal rod extending from an end of the vertical rod in a direction parallel to a flow direction of the gas stream; and an emitter provided at an end of the horizontal rod and having multiple protrusions formed on an outer surface of the emitter and each having a cutting edge, wherein the insulator is made of an electrically insulating material and provided to surround the vertical rod, one end of the insulator is disposed inside the first conductor, the other end of the insulator is disposed outside the first conductor to electrically separate the second conductor and the first conductor, and a coupling groove, to which the horizontal rod is fitted, is provided at the end of the insulator, which is disposed in the first conductor, so that a coupled state between the first conductor and the second conductor remains constantly, wherein the emitter is positioned at a center inside the first conductor, and the horizontal rod extends in a direction from the vertical rod toward an upstream of the gas stream, further comprising: an anti-arcing member provided to cover one of the two ends of the insulator which is disposed inside the first conductor, wherein the anti-arcing member is joined to the horizontal rod and made of a material having resistance to corrosion (erosion) caused by electric discharge. a first conductor provided in the form of a tubular body through which a gas stream flows and to which a ground power supply is connected; a second conductor disposed in the first conductor and having an emitter which comes into contact with the gas stream and generates non-thermal plasma; and an insulator configured to electrically separate the second conductor from the first conductor, wherein a predetermined level of direct current voltage is continuously applied to the second conductor by a high voltage applying unit, wherein the direct current voltage is -30 kV to -80 kV,, wherein the second conductor includes a vertical rod disposed in a radial direction of the first conductor; a horizontal rod extending from an end of the vertical rod in a direction parallel to a flow direction of the gas stream; and an emitter provided at an end of the horizontal rod and having multiple protrusions formed on an outer surface of the emitter and each having a cutting edge, wherein the insulator is made of an electrically insulating material and provided to surround the vertical rod, one end of the insulator is disposed inside the first conductor, the other end of the insulator is disposed outside the first conductor to electrically separate the second conductor and the first conductor, and a coupling groove, to which the horizontal rod is fitted, is provided at the end of the insulator, which is disposed in the first conductor, so that a coupled state between the first conductor and the second conductor remains constantly, wherein the emitter is positioned at a center inside the first conductor, and the horizontal rod extends in a direction from the vertical rod toward an upstream of the gas stream, further comprising: an anti-arcing member provided to cover one of the two ends of the insulator which is disposed inside the first conductor, wherein the anti-arcing member is joined to the horizontal rod and made of a material having resistance to corrosion (erosion) caused by electric discharge.