For power microrobots that work in narrow space such as inside of pipes of industrial plants, microactuators using ER microvalves that control ERF (electro-rheological fluid) flow due to the apparent viscosity change in electric fields (ER effect) have been investigated. Higher pressure can realize higher performance due to the decreased cross section of the hydraulic actuator and the decreased diameter of the pipes with lower flow rate for the same fluid power. However, the ER effect of liquid crystal type ERF is decreased when the shear rate exceeds the limit. Hence, in this study, we proposed and designed an ER microactuator considering the shear rate limit. Then we fabricated the ER microvalve using MEMS fabrication process. Finally, we clarified the characteristics of the ER microvalve, the rubber-tube microacuator, and the ER microactuator using the elements experimentally.