In designing microelectromechanical systems (MEMS), the robustness of the system critically affects long-lasting system performance. In reality, fabrication errors, material property uncertainty, and environmental uncertainty such as temperature and humidity variations affect the performance of MEMS. These factors are usually referred to as noise factors. This investigation is mainly concerned with the robust design of micro electro-thermal actuators that are to be fabricated by the MEMS fabrication technology. The baseline design is found by topology optimization method which gives an initial optimal shape of an electro-thermal actuator giving the maximum output for a given input. By the mathematical topology optimization method alone, it is difficult or impossible to consider all noise factors in the final design stage. To take into account noise factors, we will employ the robust design methodology and modify the baseline design obtained by the topology optimization. In this work, robust design will be considered with micro electro-thermal actuators. The electro-thermal actuator is an actuating device using the thermal expansion by Joule’s heat, so its performance is affected by the temperature variation of surrounding air, convection, thermal expansion, and applied voltage among others. We consider these noise factors for the final design to improve its robustness against the noise factors. Several micro electro-thermal actuators were fabricated by the MEMS fabrication technology and a series of experiments were conducted to verify the effect of the robust design concept on the final design.