In this paper we present a robotic actuation system by artificial muscle actuator based on dielectric elastomer. A novel linear actuator called “multi-stacked actuator” is presented, which can be embedded in the phalanges of the finger and ensures a compact design of the overall system. As an exemplary work, a two degree-of-freedom robot finger is developed and its performance is experimentally demonstrated. The proposed system can be extended to the multi-fingered robot hand easily, and applied even for articulated mechanisms such as legged robots etc.