Patent ID: 7895994

Claim:
An ignition device for a plasma jet ignition plug which is configured to apply a voltage to the plasma jet ignition plug in which a cavity is formed surrounding a periphery of at least a portion of a spark discharge gap formed between a center electrode and a ground electrode so as to form a discharge space, and plasma formed in the cavity is jetted from an opening formed in the cavity along with spark discharge generated in the spark discharge gap, the ignition device comprising: a discharge voltage applying unit to apply a voltage for generating the spark discharge caused by dielectric breakdown in the spark discharge gap to the plasma jet ignition plug; and an energy supplying unit to supply energy to the spark discharge gap for forming the plasma along with the spark discharge, wherein a resistor (R 1 ) is arranged between the plasma jet ignition plug and the discharge voltage applying unit to set an electric resistance value between the plasma jet ignition plug and the discharge voltage applying unit to not less than 1KΩ and not more than 20KΩ, and an electric resistance value between the plasma jet ignition plug and the energy supply unit is set to not more than 1Ω.