In this study, we aim to develop a technology to drive electrically conductive nanofibers made of polymers as an actuator. In a conventional actuator, because the potential is applied to a two-dimensional planar film shape, large electric power is necessary, the displacement is small, and application is difficult. In this research, we focus on nanofibers. Because nanofibers have a diameter of 1 mu m or less and a large specific surface area, physicochemical energy change is expected to affect the driving process. Hence, we expect to realize an actuator without a large energy loss that strongly drives using a "small, lightweight, soft, safe, and low driving voltage." Therefore, we aim to develop nanofiber actuators that are composed of unique Fe/polyurethane conductive nanofibers. As a result of the drive test of the developed nanofibers, we confirmed that the displacement became larger as the applied voltage was increased, although the voltage was as high as that of the polymer actuator; its maximum displacement was 50 mu m. With regard to the frequency characteristics, the displacement was constant up to 10 Hz.