Micro/nano robots are actively studied to realize novel techniques, such as micro/nano surgery inside the body. Recently, microorganisms, especially flagellated bacteria, have been used as the driving forces for the microobjects. To achieve the precise control of bacteria-driven microobjects, it is needed to establish the method to control the bacterial driving force. In many cases, the bacterial movements are regulated by environment. Therefore, the local environmental control technique is desired to control the bacterial driving force. We have constructed the local environmental control system with nano/micro dual pipettes, and achieved the manipulation of the transient-state of Na+-driven flagellar motor rotation by switching the local spout between Na+-containing and -free solutions. In this paper, we upgrade our nano/micro dual pipettes system to achieve the manipulation of the flagellar rotational speed in the steady-state. We demonstrate the steady-state rotational speed control of Na+-driven flagellar motor by simultaneous local spouts of Na+-containing and -free solutions with changing the spouting velocities independently.
