Robots have entered human life, and closer relationships are being formed between humans and robots. It is desirable that these robots be flexible and lightweight. For this reason, we studied and developed an artificial muscle actuator using straight-fiber-type artificial muscles derived from the McKibben-type muscles, which have excellent contraction rate and force characteristics. However, these muscles have highly nonlinear characteristics, as well as high compliance and a strong hysteresis characteristic. Hence, it is difficult to control the artificial muscle manipulator. In this study, we developed nonlinear dynamics model of the artificial muscle, investigate nonlinear dynamics characteristics of the muscle. In addition, considering nonlinear dynamic characteristics of the artificial muscle, we implore control speck of 6-DOF artificial muscle manipulator.