The present paper describes performance evaluation of a Dimethyl Ether (DME) propellant arcjet thruster. We have proposed to apply DME to arcjet thrusters owing to its favorable characteristics for space propulsion device such as non toxicity, weak chemical reactivity and storability. Thrust measurement using a vertical-pendulum-type thrust stand showed that thrust was almost monotonously increased with mass flow rate at a given discharge current, and rose with specific power. Specific impulse was also enhanced with specific power whereas thruster efficiency was attenuated. DME propellant presented higher thrust, specific power and thruster efficiency than nitrogen propellant at a given discharge current or specific power. Thrust measurement yielded a thrust of 0.19N, a specific impulse of 330s, thruster efficiency of 0.14 at a DME flow rate of 60-mg/s with the corresponding discharge voltage, power, and specific power of 90V, 2350W, and 39MJ/kg, respectively.