Abstract: A plasma ablation system includes a plasma guide wire having a conductive first electrode formed on a distal end portion, a catheter having a conductive second electrode formed on a distal end side and a lumen through which the plasma guide wire is inserted, and a radio frequency (RF) generator electrically connected to each of the plasma guide wire and the catheter to output a high frequency electric power to the first electrode and the second electrode. The plasma guide wire can ablate a living body tissue by discharge between the first electrode and the second electrode, and the RF generator outputs the high frequency electric power that is 50 W or higher and 100 W or lower during discharge and pulse-modulated to have a duty ratio of 7.4% or higher and 40.0% or lower.