Gas and Electrode Temperatures in Non-equilibrium Atmospheric Pressure Plasma with Microwave Excitation Plasma processing is the most attractive industrial technology because etching, deposition, or synthesis processings of materials are able to be performed at the low temperature. Recently, atmospheric pressure non-equilibrium plasmas expand the application in not only conventional but also new industrial and science fields. To produce non-equilibrium plasmas, several attempts have been proposed, such as corona discharges and dielectric barrier discharges. The neutral gas temperature is one of the most important plasma parameters for producing non-equilibrium atmospheric pressure plasma. The gas temperature measured gives us the information concerning the chemical reaction in the plasma such as combination and elimination reaction. Excess high gas temperature causes the evaporation of electrodes for producing the plasma, and the melting of materials by the plasma irradiation. In this study, non-equilibrium atmospheric pressure plasma was successfully produced in N@sub 2@, Ar, or He gas using a dielectric barrier micro-gap plasma with microwave excitation. We investigated effects of pulse discharge and electrode temperature on gas temperature. We measured gas temperature by N@sub 2@ optical emission of the second positive band system and electrode temperature by blackbody emission. It was found that the short pulse modulation of microwave power and water-cooled electrode were effective for reducing the gas temperature. The pulse discharge decreased the gas temperature from 900 K to 600 K, and the water-cooled electrode decreased the gas temperature by more than 200 K. Controlling of the electrode temperature was one of the most effective techniques to reduce the gas temperature because the gas temperature was in equilibrium with the electrode temperature.