We have proposed a prototype model of walking micro robot using IPMC (Ionic Polymer Metal Composite) actuators. The stiffness of IPMC actuator is a key parameter to implement a walking robot. Therefore, the casting process is developed to increase the stiffness of the actuator by controlling thickness of ion-exchange polymer film. The process of fabricating a solid film front liquid state of ion-exchange polymer is difficult since any process parameter and handling material are not disclosed and has to be set by trial and error. The bending characteristics and generative tip force of IPMC actuator under variation of thickness and length of the actuator and voltage input are investigated. Also, mechanical model is derived to predict the generative tip force and displacement of IPMC actuator according to the variation of thickness. With cast film based IPMC actuators, a ciliary type 8-legged micro robot, which can be operated in aqueous surroundings like inside of human body, is constructed and tested. The robot shows good reliability and can reach up to 17 mm/min in speed.