In general, it is said that the pneumatic servo system is unsuitable for complex controls and limited in application. However, from the characteristics of the air compression, it is desirable that the pneumatic robot develops for the flexible manipulation. The main problems which exist in the pneumatic servo system are the existences of both solid friction and a dead time. This paper proposes a design method of robustness servo controller to solve above problems. The design method of robust servo controller for pneumatic manipulator is described as follows. First, the model of the pneumatic manipulator is derived and the influence of the solid friction is examined on the position control. Second, the design specification of control system are drawn up, and then it is shown that the robust servo problem is reduced to the mixed sensitivity problem. Third, the design technique of the controller is proposed based on state feedback H∞ control theory. From the viewpoint of robustness, this technique has the superior advantage, comparing with the other technique estimating plant like the disturbance observer and the adaptive control. Finally, the characteristics of the H∞ servo control system is analyzed, and the effectiveness is verified through the experiment and the simulation.