Provided is a high voltage driving device including a housing and a cathode, an anode, and an insulation structure, which are disposed in the housing. Here, the cathode and the anode are spaced apart from each other with the insulation structure therebetween. Also, the insulation structure includes a first solid insulator disposed adjacent to the cathode and a second solid insulator disposed adjacent to the anode. Also, the first solid insulator has first volumetric resistivity less than second volumetric resistivity of the second solid insulator, and the first solid insulator contacts the cathode.