Soft actuators should have flexible body and be controlled by external inputs. For soft actuator development, it is very important which materials are utilized. Silicone is a typical material for soft actuators and has high flexibility and versatility. We developed a new material actuator by adding the electrical conductivity of tri-iron tetra-oxide to the silicone material properties. We show the whole fabrication process for the actuator. And, for the detailed characteristic investigation, we conduct actuation test of the developed beam type actuator. First, the electrostatic attraction force is applied to the actuator. We show that the actuator is controlled as the amplitude and frequency of the input voltage potential. Also, we searched its resonant frequency for larger motion. In addition, we tested the actuator in influence of magnet and confirm that it works well. It is expected that the actuator can be adapted to various robot researches.