A Soft Robot inspired from natural systems is one of the main topics in robotic field. Accordingly, artificial muscles were widely investigated due to their potentials in soft robots. We propose here a novel micro artificial muscle actuator (< 1 cm3) utilizing the electro-conjugate fluid (ECF) generating powerful jet flow when subjected to a high voltage (< 10 kV). The actuator mainly consists of a fiber-reinforced silicone rubber tube and a micro pressure source using ECF. The tube contracts along the actuator axis with increasing pressure by ECF jet. The experimental results confirm the effectiveness of the proposed actuation technology.