This paper presents a new structural optimization method for the design of compliant electro thermal micro actuators based on the level set method and the Finite Element Method (FEM). Compliant electro thermal actuator designed to be flexible to achieve a specified motion as a actuator by intentionally designing configurations that exploit thermal expansion effects in elastic material when appropriate portions of the actuator structure are imposed electric voltage. First, an optimization problem is formulated that addresses the design of compliant electro thermal micro actuators considering the magnitude of the displacement at the output location. Based on the optimization formulation and the level set method, a new structural optimization algorithm is constructed that employs the FEM when solving the equilibrium equations and updating the level set function. Finally, a design example is provided to confirm the usefulness of the proposed structural optimization method.