Flexible actuator is a kind of actuator which consists of linear motor and thrust wire. Its characteristic is to transmit the force from tip to tip. Therefore, it is possible to design light weight robot without considering the location of actuator. Thanks to this advantage, it is useful for many kinds of robot- teleoperational robot, finger robot, and so on. However, force transmission ability of thrust wire is not constant and can be changed by some factors. In particular, backlash, friction, deflection and posture of thrust wire are main problem points. Conventional researches about backlash and friction have already been conducted and compensation methods have been proposed. However, the influence of thrust wire's posture has not been researched yet. For this reason, the force transmission ability by changing its posture of is analyzed in this paper. In order to analyze, a cantilever model based on material mechanics is applied to thrust wire. The analysis of proposed model is conducted by experiment.