This paper considers the positioning of a motor in a vacuum gate valve which is used in a vacuum chamber. First, by using reinforcement of bearings' stiffness with permanent magnets, the fluctuation of the valve is suppressed. Next, by adjusting command signals and MR sensor's outputs, the repeatability of the positioning is improved. Moreover, three-dimensional dynamic analysis of the motor is performed by using magnetic analysis software "MagNet7." Simulation results agree with experimental results. Finally, sequential operation of the valve is performed without mechanical contact in atmosphere and vacuum.