To understand the mechanism of surface processing using atmospheric-pressure non-equilibrium plasma jets, we measured the vibrational and rotational temperatures in the plasmas by optical emission spectroscopy. Plasma was excited using a high-frequency pulsed power supply, using a gas mixture of Ar (20 L⁄min) and N2 (0.1 to 0.5 L⁄min) as the plasma gas, and changing the flow rate of N2 gas at an i